Hello, Suman!
Thanks for your reply!
I followed your steps, but it didn't work and didn't find anything in the logs.
I have managed to recreate the issue on a test server. There were only the default users and another test user introduced manually. After I ran
UPDATE cmn_sec_users SET timezone = 'Europe/Bucharest';
I could no longer login with admin user.
I restarted server because the services could no longer be stopped.
I set every user's timezone to its original value directly in Oracle and then I could login again.
I tried to do the same thing on the original server, but it doesn't work. I'm not sure I set the timezones correctly for each user.
Is the default setting for LDAP imported users America/Chicago?
Thank you!