After some time of research I found this post no-login-possible-white-page
which pointed me to https://securityheaders.com/ where I found out HTTP/1.1 was “500 Internal Server Error”.
I started looking for that and got to this site http-error-500-after-update-to-nc-13 with somebody suggesting to do
sudo -u www-data php occ upgrade
Doing so led to this:
~# /opt/plesk/php/7.3/bin/php occ upgrade
PHP Fatal error: Allowed memory size of 2097152 bytes exhausted (tried to allocate 4096 bytes) in /var/www/vhosts/my.domain/nextcloud.my.domain/3rdparty/composer/autoload_static.php on line 2098
Bringing me to this page allowed-memory-size-of…
I set memory_limit to “-1” and now I can access nextcloud again.
Strange thing is, I had already undone my previous change setting memory_limit to 16GB by setting value to 128MB which is the default.
Hopefully this will help someone sometime.
Best regards