Checking the Icingaweb2 logs I found the following messages, I 'don't know whether they really mean any issue, I am just curious what does it mean:
Can't get group memberships for user 'myuser' from backend 'Extragroups - rule-based group membership'. An exception was thrown: Icinga\Exception\ConfigurationError in /usr/share/php/Icinga/Authentication/UserGrou
p/UserGroupBackend.php:137 with message: Configuration for user group backend "Extragroups - rule-based group membership" defines an invalid backend type. Backend type "extragroups" is not supported