Join Domain failing

[jmyers83]

I was trying to join my TNAS F5-422 (TOS 4.2.40-2107221409) to my windows AD domain but I am getting "Operation Failed!" error with no other information. I have been trying to find some sort of guide/documentation to make sure I am entering my domain info correctly but I have tried so many different things and cannot get it to work. The closest I have gotten results in bad username or password events in my Domain Controller for the Administrator user I am trying to use for the binding.

Can you share some documentation on how this is supposed to be setup?

I have tried many different ways for the admin user authentication page but nothing ever works:

"DOMAIN\username"
"username@domain.com"
"username"
"CN=username,CN=Users,DC=domain,DC=com"

[TMSupport]

Which windows version are you using?
Check whether the domain info filled in contains spaces?
Use the user and password you filled in to see if you can log in to the domain.

[TMroy]

The authentication for AD domain has been optimized in TOS 5, it is recommended to try the new version.

[jmyers83]

No spaces in the domain name. Confirmed I used the correct password. Tried it against Windows Server 2016 and Server 2019 on the same domain.

Can I update to TOS 5.x without losing any data?

[TMSupport]

Reinstalling the system will not delete the data on your hard drive theoretically, but for safety considerations, please back up your data in advance.
TOS 5 Update Notes