error in default apache log – /var/log/apache2/error.log
AH01071: Got error 'PHP message: PHP Fatal error: Array and string offset access syntax with curly braces is no longer supported in /usr/share/phpmyadmin/libraries/url_generating.lib.php on lin e 231'
If you instaled an additional version of PHP to a server in recent times, there is a possibility the apache is reconfigured to use the new version of PHP to run PHPMyAdmin and not the default one.
You can check this by creating a new file, for example, status.php in PHPMyAdmin folder /usr/share/phpmyadmin with this content.
Then you can check the URL HTTP://YOURSERVER.TLD/phpmyadmin/status.php. If the showed PHP version is not the same as the default version of your ISPConfig install then you need probably disconfigure the PHP version. In my case, I had installed a new version of PHP 8.1. Then I need disconfigure this version by this command.
root@webhosting:/usr/share/phpmyadmin# a2disconf php8.1-fpm Conf php8.1-fpm disabled. To activate the new configuration, you need to run: systemctl reload apache2 root@webhosting:/usr/share/phpmyadmin# systemctl reload apache2