XMPP auth failing - New Year's Present?

NethServer Version: 7.7.1908
Module: chat / ejabberd

my server is running in a different timezone and I started getting this error in the log exactly at 6 AM:

2020-01-01 06:00:21.613 [error] <0.2582.0>@ejabberd_auth_external:failure:103 External authentication program failed when calling ‘check_password’ for derek@mydomain.com: disconnected

Any help would be greatly appreciated as this is my primary method of chatting and receiving SMS!

Actually, just to clarify that it’s trying to auth against: derek@neth.mydomain.com instead of derek@mydomain.com. In the past I have always authenticated as derek@mydomain.com - why the sudden change after the new year?

Not sure if it is related, but I removed a secondary network interface that was for LAN connections only and now I can connect again.

@stephdl, @federico.ballarini, @davidep: Guys, have you looked this problem?

@djx: Can you add a new time a secondary network interface and confirm this problem?

Thanks in advance.

Sorry for the lack of detail on this. When trying to edit the network to solve this issue I ran into other problems.

There were no configuration changes before this started. I looked closer at the log and the entry is actually like this:

2020-01-01 06:00:21.613 [error] <0.2582.0>@ejabberd_auth_external:failure:103 External authentication program failed when calling 'check_password' for derek@neth.mydomain.com: disconnected

So we can see that for some reason it is trying to auth with the Nethserver subdomain in the username, even though usernames are like derek@mydomain.com.