So here's the trace:

[2021-03-21 00:52:09] flarum.ERROR: RuntimeException: Tag 'IMG' does not exist in /data/wwwroot/community.wvbtech.com/vendor/s9e/text-formatter/src/Configurator/Collections/TagCollection.php:34
Stack trace:
#0 /data/wwwroot/community.wvbtech.com/vendor/s9e/text-formatter/src/Configurator/Collections/NormalizedCollection.php(185): s9e\TextFormatter\Configurator\Collections\TagCollection->getNotExistException()
#1 /data/wwwroot/community.wvbtech.com/vendor/s9e/text-formatter/src/Configurator/Collections/NormalizedCollection.php(241): s9e\TextFormatter\Configurator\Collections\NormalizedCollection->get()
#2 /data/wwwroot/community.wvbtech.com/vendor/fof/secure-https/src/Listeners/ModifyContentHtml.php(42): s9e\TextFormatter\Configurator\Collections\NormalizedCollection->offsetGet()
#3 /data/wwwroot/community.wvbtech.com/vendor/illuminate/events/Dispatcher.php(369): FoF\SecureHttps\Listeners\ModifyContentHtml->configuring()
#4 /data/wwwroot/community.wvbtech.com/vendor/illuminate/events/Dispatcher.php(218): Illuminate\Events\Dispatcher->Illuminate\Events\{closure}()
#5 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Formatter/Formatter.php(157): Illuminate\Events\Dispatcher->dispatch()
#6 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Formatter/Formatter.php(192): Flarum\Formatter\Formatter->getConfigurator()
#7 /data/wwwroot/community.wvbtech.com/vendor/illuminate/cache/Repository.php(418): Flarum\Formatter\Formatter->Flarum\Formatter\{closure}()
#8 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Formatter/Formatter.php(193): Illuminate\Cache\Repository->rememberForever()
#9 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Formatter/Formatter.php(226): Flarum\Formatter\Formatter->getComponent()
#10 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Formatter/Formatter.php(102): Flarum\Formatter\Formatter->getRenderer()
#11 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Post/CommentPost.php(172): Flarum\Formatter\Formatter->render()
#12 /data/wwwroot/community.wvbtech.com/vendor/v17development/flarum-seo/src/Managers/Discussion.php(101): Flarum\Post\CommentPost->formatContent()
#13 /data/wwwroot/community.wvbtech.com/vendor/v17development/flarum-seo/src/Managers/Discussion.php(41): V17Development\FlarumSeo\Managers\Discussion->createTags()
#14 /data/wwwroot/community.wvbtech.com/vendor/v17development/flarum-seo/src/Listeners/PageListener.php(155): V17Development\FlarumSeo\Managers\Discussion->__construct()
#15 /data/wwwroot/community.wvbtech.com/vendor/v17development/flarum-seo/src/Listeners/PageListener.php(120): V17Development\FlarumSeo\Listeners\PageListener->determine()
#16 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Foundation/ContainerUtil.php(30): V17Development\FlarumSeo\Listeners\PageListener->__invoke()
#17 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Frontend/Frontend.php(63): Flarum\Foundation\ContainerUtil::Flarum\Foundation\{closure}()
#18 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Frontend/Frontend.php(55): Flarum\Frontend\Frontend->populate()
#19 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Frontend/Controller.php(32): Flarum\Frontend\Frontend->document()
#20 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/RouteHandlerFactory.php(38): Flarum\Frontend\Controller->handle()
#21 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/ExecuteRoute.php(27): Flarum\Http\RouteHandlerFactory->Flarum\Http\{closure}()
#22 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ExecuteRoute->process()
#23 /data/wwwroot/community.wvbtech.com/vendor/fof/oauth/src/Middleware/ErrorHandler.php(50): Laminas\Stratigility\Next->handle()
#24 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\OAuth\Middleware\ErrorHandler->process()
#25 /data/wwwroot/community.wvbtech.com/vendor/reflar/recache/src/Middlewares/CacheResponse.php(83): Laminas\Stratigility\Next->handle()
#26 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Reflar\ReCache\Middlewares\CacheResponse->process()
#27 /data/wwwroot/community.wvbtech.com/vendor/fof/pwned-passwords/src/Middleware/CheckPasswordReset.php(64): Laminas\Stratigility\Next->handle()
#28 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\PwnedPasswords\Middleware\CheckPasswordReset->process()
#29 /data/wwwroot/community.wvbtech.com/vendor/fof/pwned-passwords/src/Middleware/CheckLoginPassword.php(53): Laminas\Stratigility\Next->handle()
#30 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\PwnedPasswords\Middleware\CheckLoginPassword->process()
#31 /data/wwwroot/community.wvbtech.com/vendor/fof/pwned-passwords/src/Middleware/PreventPwnedPassword.php(71): Laminas\Stratigility\Next->handle()
#32 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\PwnedPasswords\Middleware\PreventPwnedPassword->process()
#33 /data/wwwroot/community.wvbtech.com/vendor/fof/terms/src/Middlewares/RegisterMiddleware.php(48): Laminas\Stratigility\Next->handle()
#34 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\Terms\Middlewares\RegisterMiddleware->process()
#35 /data/wwwroot/community.wvbtech.com/vendor/fof/stopforumspam/src/Middleware/RegisterMiddleware.php(101): Laminas\Stratigility\Next->handle()
#36 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\StopForumSpam\Middleware\RegisterMiddleware->process()
#37 /data/wwwroot/community.wvbtech.com/vendor/fof/secure-https/src/Middlewares/ContentSecurityPolicyMiddleware.php(32): Laminas\Stratigility\Next->handle()
#38 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\SecureHttps\Middlewares\ContentSecurityPolicyMiddleware->process()
#39 /data/wwwroot/community.wvbtech.com/vendor/fof/ban-ips/src/Middleware/RegisterMiddleware.php(93): Laminas\Stratigility\Next->handle()
#40 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): FoF\BanIPs\Middleware\RegisterMiddleware->process()
#41 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/ShareErrorsFromSession.php(57): Laminas\Stratigility\Next->handle()
#42 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ShareErrorsFromSession->process()
#43 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/CheckCsrfToken.php(40): Laminas\Stratigility\Next->handle()
#44 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\CheckCsrfToken->process()
#45 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/ResolveRoute.php(67): Laminas\Stratigility\Next->handle()
#46 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ResolveRoute->process()
#47 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/SetLocale.php(50): Laminas\Stratigility\Next->handle()
#48 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\SetLocale->process()
#49 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/AuthenticateWithSession.php(32): Laminas\Stratigility\Next->handle()
#50 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\AuthenticateWithSession->process()
#51 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/RememberFromCookie.php(51): Laminas\Stratigility\Next->handle()
#52 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\RememberFromCookie->process()
#53 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/StartSession.php(61): Laminas\Stratigility\Next->handle()
#54 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\StartSession->process()
#55 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/CollectGarbage.php(46): Laminas\Stratigility\Next->handle()
#56 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\CollectGarbage->process()
#57 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/ParseJsonBody.php(28): Laminas\Stratigility\Next->handle()
#58 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ParseJsonBody->process()
#59 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Middleware/HandleErrors.php(57): Laminas\Stratigility\Next->handle()
#60 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\HandleErrors->process()
#61 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(84): Laminas\Stratigility\Next->handle()
#62 /data/wwwroot/community.wvbtech.com/vendor/middlewares/request-handler/src/RequestHandler.php(84): Laminas\Stratigility\MiddlewarePipe->process()
#63 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\RequestHandler->process()
#64 /data/wwwroot/community.wvbtech.com/vendor/middlewares/base-path-router/src/BasePathRouter.php(97): Laminas\Stratigility\Next->handle()
#65 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\BasePathRouter->process()
#66 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Middleware/OriginalMessages.php(42): Laminas\Stratigility\Next->handle()
#67 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Laminas\Stratigility\Middleware\OriginalMessages->process()
#68 /data/wwwroot/community.wvbtech.com/vendor/middlewares/base-path/src/BasePath.php(53): Laminas\Stratigility\Next->handle()
#69 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\BasePath->process()
#70 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(84): Laminas\Stratigility\Next->handle()
#71 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(73): Laminas\Stratigility\MiddlewarePipe->process()
#72 /data/wwwroot/community.wvbtech.com/vendor/laminas/laminas-httphandlerrunner/src/RequestHandlerRunner.php(96): Laminas\Stratigility\MiddlewarePipe->handle()
#73 /data/wwwroot/community.wvbtech.com/vendor/flarum/core/src/Http/Server.php(42): Laminas\HttpHandlerRunner\RequestHandlerRunner->run()
#74 /data/wwwroot/community.wvbtech.com/public/index.php(39): Flarum\Http\Server->listen()
#75 {main}

The error occurred after executing the following command:

composer require zerosonesfun/direct-links jslirola/flarum-ext-login2seeplus fof/doorman ianm/flarum-diff:2.0.0-beta.1 ianm/follow-users askvortsov/flarum-markdown-tables:* askvortsov/flarum-checklist:*

It's weird because none of them were enabled after the composer has done its job 🤔
Here's the php flarum info output for now:

[root@main community.wvbtech.com]# php flarum info
PHP Warning:  PHP Startup: Unable to load dynamic library 'pdo_mysql' (tried: /usr/lib64/php/modules/pdo_mysql (/usr/lib64/php/modules/pdo_mysql: cannot open shared object file: No such file or directory), /usr/lib64/php/modules/pdo_mysql.so (/usr/lib64/php/modules/pdo_mysql.so: undefined symbol: mysqlnd_allocator)) in Unknown on line 0
PHP Warning:  PHP Startup: Unable to load dynamic library 'gd' (tried: /usr/lib64/php/modules/gd (/usr/lib64/php/modules/gd: cannot open shared object file: No such file or directory), /usr/lib64/php/modules/gd.so (libfribidi.so.0: cannot open shared object file: No such file or directory)) in Unknown on line 0
PHP Warning:  PHP Startup: Unable to load dynamic library 'zip.so' (tried: /usr/lib64/php/modules/zip.so (/usr/lib64/php/modules/zip.so: undefined symbol: zip_register_cancel_callback_with_state), /usr/lib64/php/modules/zip.so.so (/usr/lib64/php/modules/zip.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
Flarum core 0.1.0-beta.15
PHP version: 7.4.16
Loaded extensions: Core, date, libxml, openssl, pcre, zlib, filter, hash, pcntl, readline, Reflection, SPL, session, standard, bz2, calendar, ctype, curl, dom, mbstring, fileinfo, ftp, gettext, gmp, iconv, intl, json, exif, mysqlnd, PDO, Phar, posix, shmop, SimpleXML, sockets, sqlite3, sysvmsg, sysvsem, sysvshm, tokenizer, xml, xmlwriter, xsl, mysqli, pdo_mysql, pdo_sqlite, xmlreader
+---------------------------------+------------------+--------+
| Flarum Extensions               |                  |        |
+---------------------------------+------------------+--------+
| ID                              | Version          | Commit |
+---------------------------------+------------------+--------+
| flarum-approval                 | v0.1.0-beta.15   |        |
| flarum-emoji                    | v0.1.0-beta.15   |        |
| flarum-lang-english             | v0.1.0-beta.15   |        |
| flarum-flags                    | v0.1.0-beta.15   |        |
| flarum-lock                     | v0.1.0-beta.15   |        |
| flarum-markdown                 | v0.1.0-beta.15   |        |
| flarum-statistics               | v0.1.0-beta.15   |        |
| flarum-sticky                   | v0.1.0-beta.15   |        |
| flarum-subscriptions            | v0.1.0-beta.15   |        |
| flarum-suspend                  | v0.1.0-beta.15   |        |
| flarum-tags                     | v0.1.0-beta.15   |        |
| flarum-akismet                  | v0.1.0-beta.15   |        |
| flarum-embed                    | v0.1.0-beta.15   |        |
| askvortsov-categories           | v2.0.0           |        |
| askvortsov-moderator-warnings   | v0.4.2           |        |
| fof-ban-ips                     | 0.4.0            |        |
| fof-best-answer                 | 0.3.6            |        |
| fof-byobu                       | 0.6.1            |        |
| fof-disposable-emails           | 0.2.1            |        |
| fof-follow-tags                 | 0.6.5            |        |
| fof-geoip                       | 0.3.0            |        |
| fof-ignore-users                | 0.3.1            |        |
| fof-linguist                    | 0.5.1            |        |
| fof-links                       | 0.5.4            |        |
| fof-merge-discussions           | 0.5.1            |        |
| fof-nightmode                   | 0.7.1            |        |
| fof-pages                       | 0.5.1            |        |
| fof-polls                       | 0.3.2            |        |
| fof-pretty-mail                 | 0.3.0            |        |
| fof-prevent-necrobumping        | 0.4.0            |        |
| fof-profile-image-crop          | 0.2.1            |        |
| fof-reactions                   | 0.5.0            |        |
| fof-secure-https                | 0.3.0            |        |
| fof-sitemap                     | 0.6.0            |        |
| fof-socialprofile               | 0.2.3            |        |
| fof-spamblock                   | 0.4.0            |        |
| fof-split                       | 0.6.0            |        |
| fof-stopforumspam               | 0.4.0            |        |
| fof-upload                      | 0.13.1           |        |
| fof-user-directory              | 0.5.3            |        |
| fof-username-request            | 0.4.2            |        |
| fof-recaptcha                   | 0.3.1            |        |
| flarum-mentions                 | v0.1.0-beta.15   |        |
| michaelbelgium-profile-views    | v4.0.0           |        |
| fof-impersonate                 | 0.7.0            |        |
| flarum-pusher                   | v0.1.0-beta.15   |        |
| fof-drafts                      | 0.3.2            |        |
| clarkwinkelmann-author-change   | 0.2.2            |        |
| fof-terms                       | 0.6.1            |        |
| fof-pwned-passwords             | 0.6.2            |        |
| fof-gamification                | 0.4.3            |        |
| fof-analytics                   | 0.11.0           |        |
| askvortsov-discussion-templates | v0.5.0           |        |
| fof-realtimedate                | 0.2.1            |        |
| fof-html-errors                 | 0.5.0            |        |
| reflar-recache                  | 2.3.2            |        |
| flarum-bbcode                   | v0.1.0-beta.15   |        |
| nearata-copy-code-to-clipboard  | v1.2.0           |        |
| fof-frontpage                   | 0.3.0            |        |
| fof-user-bio                    | 0.4.2            |        |
| v17development-seo              | v1.6.2           |        |
| ffans-lang-simplified-chinese   | v0.1.0-beta.15.2 |        |
| fof-oauth                       | 0.2.1            |        |
| fof-doorman                     | 0.3.0            |        |
| ianm-diff                       | 2.0.0-beta.1     |        |
| fof-formatting                  | 0.3.1            |        |
| lcinhk-acgembed                 | v0.5.2           |        |
+---------------------------------+------------------+--------+
Base URL: https://community.wvbtech.com
Installation path: /data/wwwroot/community.wvbtech.com
Debug mode: ON