I am running an Installation for a school with about 600 User. Until last week the Installation von all-inkl.com works quite well, but suddenly we have the following situation:
A user logs in and has for example the session_id=62e6b05c3a6f5601a25c2c63090cd40b. After a while, several error show in the log (Browser and Server):
Browser:
File could not be loaded. Please check your internet connection
Reason: the session_id changes in the background to d92ce1d537241aeeda20c270a6d2c88c (example). The user can reload the page sometimes an go on with his work or is logged out in the worst case.
CSRF check failed
Server log Nextcloud
OC\AppFramework\Middleware\Security\Exceptions\CrossSiteRequestForgeryException: CSRF check failed and many more
Happens with every user and in all browsers.
Nextcloud version (eg, 18.0.4):
Operating system and version (eg, Ubuntu 16.04):
Apache 2.4.25)_:
PHP version 7.3:
Has anyone an idea, how to solve this?