darrendriven This error indicates a corrupted or incomplete Composer installation within your Flarum vendor directory.
Specifically, the Flarum Extension Manager is trying to run an update, but it cannot find a core Composer class (JsonConfigSource). This usually happens when a previous update was interrupted, or if there is a version mismatch between Flarum's requirements and the files currently on your server.
Since the error is happening inside the vendor folder, you cannot fix this through the Flarum Admin UI. You must use SSH to fix it.
Log in to your server via SSH and navigate to your Flarum root directory:
cd /home/u919619080/domains/ngna.us/public_html
Delete the corrupted vendor folder and lock file:
rm -rf vendor
rm composer.lock
Clear the Composer cache to ensure no corrupted files are re-downloaded:
composer clear-cache
Reinstall all dependencies:
composer install
Clear Flarum's internal cache:
php flarum cache:clear
