User Mangement - Loading wheel don't work (10.6), users list hiden

[Translation by Google from French to English]
Yesterday I updated version 10.5 to 10.6 with the tool from Softaculous

When I want to access user management, the loading wheel does not activate. So the user list is empty and I cannot access any options on the left margin.

I have consulted some forum posts which advise to go directly to the Apache server (with PuTTy) and use the OCC “user: sync” command

Thanks alot jvillafanez. It works. Details as below
I’m not using any external source so I ran following command to list my current source
sudo -u www-data ./occ user: sync -l
which returned OC \ User \ Database
I then ran
sudo -u www-data ./occ user: sync “OC \ User \ Database”
I selected option 2 to be safe and all my users are now showed up.
However, there is a group has number 1 indicates 1 user but it is not listed. I just deleted that group and recreated it and all good now.
Why don’t upgrade process run this command as well or leave a note?

I am not very skilled in OCC mode. Would correcting data directly in the MySQL DB (with phpMyAdmin) be possible? Which tables / fields should be synchronized?

Thank you for your attention and understanding, and Happy Holidays.