Hey Devin-
I also responded to your ticket... but just so others know, this is basically an error saying the SMTP server is not allowing the UBB to send mail out.
Since the rules for relay can vary from host to host, its hard to say what exactly is causing the error, but a good place to start is to make sure that your registration email (the one that all your registration related emails use as the 'from' address) is from your domain. So, for instance, if your domain is xy.com, make sure that your registration email is []
[email protected].[/]
In your case Devin, it seems as though you are using an address from your domain, so thats good.
But the error says:
53 sorry, that domain isn't allowed to be relayed thru this MTA (#5.7.1)
The SMTP server has rejected the email address the UBB tried to send mail to.
It sounds to me as if they aren't allowing third-party programs to relay mail through your domain at all.
You'll need to check with your host for sure.