VDP Replication - password not working in 6.1

I replaced old VDP 6.0.2 instances with the new VDP 6.1.

The actual backups seem to be working correctly, but I had 2 VDP instances replicating to an offsite VDP instance.

I am trying to re-set up the replication (all instances are now on 6.1), but when I try authenticating with the remote instance, I keep getting an error message saying "Authentication failed. Modify destination network settings, username, password, or path and then click "Verify Authentication" to verify authentication again."

I tried both the repluser and root users, where I got the same error.

Any ideas?