Unable to connect to Samba AD

New user of TrueNAS SCALE here trying to connect to a remote Samba AD. First attempt using just the Basic parameters gives up with:

Strong(er) authentication required: BindSimple: Transport encryption required.

So delve into the advanced section and turn on encryption mode. This fails with:

[EINVAL] ldap_update: [SERVER_DOWN]: Can’t contact LDAP server: (unknown error code)

Not the most helpful error message. Selecting More info doesn’t give anything useful either. As the transport is now encrypted, I can’t can’t run a capture on the packets an see what’s going down the wire for clues.

I’m running Dragonfish-24.04.2 and the Samba is smbd version 4.18.6-Ubuntu.

Any ideas where to look next.

Why are you using the LDAP plugin to try to bind to AD? We have an activedirectory plugin explicitly for this purpose.