I got an error after installation:
[2021-03-07 21:46:37] flarum.ERROR: TypeError: Argument 1 passed to Flarum\Formatter\Event\Rendering::__construct() must be an instance of s9e\TextFormatter\Renderer, instance of PHP_Incomplete_Class given, called in /home/xxx/xxx/vendor/flarum/core/src/Formatter/Formatter.php on line 105 and defined in /home/xxx/xxx/vendor/flarum/core/src/Formatter/Event/Rendering.php:46
Stack trace:
#0 /home/xxx/xxx/vendor/flarum/core/src/Formatter/Formatter.php(105): Flarum\Formatter\Event\Rendering->construct(Object(__PHP_Incomplete_Class), Object(Flarum\Post\CommentPost), '<r><p>U Odjelje...', Object(Laminas\Diactoros\ServerRequest))
#1 /home/xxx/xxx/vendor/flarum/core/src/Post/CommentPost.php(172): Flarum\Formatter\Formatter->render('<r><p>U Odjelje...', Object(Flarum\Post\CommentPost), Object(Laminas\Diactoros\ServerRequest))
#2 /home/xxx/xxx/vendor/flarum/core/src/Api/Serializer/BasicPostSerializer.php(44): Flarum\Post\CommentPost->formatContent(Object(Laminas\Diactoros\ServerRequest))
#3 /home/xxx/xxx/vendor/flarum/core/src/Api/Serializer/AbstractSerializer.php(95): Flarum\Api\Serializer\BasicPostSerializer->getDefaultAttributes(Object(Flarum\Post\CommentPost))