A second effect appears : It takes minutes to set the content of the CB configuration when selected in the menu...
Probably the version checks. There's an HTTP request sent to our server for CB version check in CB > Configuration. You can change this to Manual instead of Automatic checking within CB > Configuration > Integrations.
Is there any reason for it ? Have you any idea about the specific adresse or URL ...that have to be connected or identified to make it work correctly without disconnect the filter and be out of law ... ?
No idea, your issue again regarding login has nothing to do with CB. Don't use two factor authentication or find out which Google addresses you need to allow through (guessing a firewall?). You can also try using the TFA Google plugin built into Joomla instead of a 3rd party extension to see if Joomlas works fine.
Well many thanks for your answer... I investigated further and realized that CB user manager takes into account the last visit only if users disconnect themselves from the front-end.
If users quit the application, or if they close their browser without having disconnected their session, then nothing appears on the report.
Is there a reason for not disconnecting user after a lap of time ?
CB doesn't set or handle lastVisitDate. That is a Joomla column entirely controlled by Joomla login API. It should be set immediately on login (confirmed in my tests) and on logout (also confirmed in my tests). Specifically this is set in Joomlas user plugin plugins/user/joomla/joomla.php (see onUserLogin and onUserLogout). If something is intercepting those events though then my guess is they aren't being fired and setLastVisit can't be called.