I found the following warnings in the Security & setup warnings settings of Nexcloud:
You are currently running PHP 7.3.31-1~deb10u1. Upgrade your PHP version to take advantage of performance and security updates provided by the PHP Group as soon as your distribution supports it.
Nextcloud 23 is the last release supporting PHP 7.3. Nextcloud 24 requires at least PHP 7.4.
So I installed php 7.4. This is what I get when I run php -v:
PHP 7.4.29 (cli) (built: Apr 22 2022 06:44:32) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
with Zend OPcache v7.4.29, Copyright (c), by Zend Technologies
@Operations, Thank you for the suggestion. When I ran those commands, followed by sudo service apache2 restart the site stopped working. The following text was being displayed in the browser:
Internal Server Error
The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log.
Not knowing which server logs to examine, I attempted syslog and nextcloud.log but didn’t find anything useful to me, possibly because I didn’t know what I was looking at.
When I reversed the process, the site came back up.