Users getting logged out after starting to use nextcloud as a group

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Nextcloud version 14.0.0
Operating system and version unknown (currently no access to webserver plesk based)
Apache or nginx version Unknown
PHP version 7.x

The issue you are facing:

I installed nextcloud earlyer today and start to configure it. packed my stuff, got to school and started to add user profiles (25 users overall).
up to this point there was not a single problem i faced (wasn’t looking into the logs)
at the moment i “opened” the floodgate to my classmates, everyone including myself were getting logged out after a few seconds of beeing logged in, logging back in works fine, but after a few moments, again, getting logged out.
i’m currently at my schools pc where my webspace&ftp access is blocked, i’ll try to get as much informations as possible later (in about 6-8 hours), but in case someone might have an idea, i’ll post this much information right now.
thanks for the help in advance
Sven ‘Cormac’

PS: everyone is using webbased logins because of not beeing allowed to install our own software on the pcs

Is this the first time you’ve seen this error? yes

Steps to replicate it: (most likly a lokal anomaly)

The output of your Nextcloud log in Admin > Logging:
is_readable(): open_basedir restriction in effect. File(/proc/meminfo) is not within the allowed path(s): (/var/www/vhosts/cormacaers.de/:/tmp/) at /var/www/vhosts/cormacaers.de/httpdocs/nextcloud/apps/serverinfo/lib/SystemStatistics.php#96
(getting spamed by it)

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
Currently no access (school pc is blocking access)