I have the same issue with 25.10.2.1. I’m trying to join it to a Samba 4 Active directory and I get errors that it can’t find my PDC. My DNS is setup correctly, I have all the required SRV records. I’m able to join a Windows 11 computer to this active directory without any issue and I can login to the Windows 11 computer with credentials from the AD but TrueNAS scale refuses to join.