This has been an old problem for me since I started configuring Ubuntu to login with MS Active Directory. I thought the problem was solved in v22.04 but it still remains. I have followed the procedure on https://ubuntu.com/server/docs/how-to-set-up-sssd-with-active-directory, everything run smoothly, no error messages, perfect DNS resolution.
When testing, sometimes users login, sometimes they don't. I know Ubuntu is contacting the AD and it answers back since after a timeout there is a message showing: "Your password will expire in 6 day(s).". After several attempts, I finally get in. After how many attempts? it is just random.
I have checked all the logs at /var/log/sssd, no errors there, just an informational krb5 message saying "No mapping for user@domain", I think Kerberos is optional here.
Any ideas?