I don't think .local was ever accepted, even back in 5.2.42 your exact scenario occurs, as seen here
So you would need to call Xerox official to either do a Spar (Fix if it's broken) or a FER (Feature enhancement request- to get 5 extensions supported)
If you call Xerox, feel free to give them the link to this, they won't stumble on to it since this is a peer to peer forum, Xerox Support doesn't use it (I'm an exception as I am here unofficially)
I am configuring the Site Administrator e-mail and I am unable to use the format <username>@<domain>.<extension> where the extension=5 letters. firstname.lastname@example.org. I can however use a 4-letter extension suca as email@example.com.
The attached file has screen shots of the unaccepted format--with error message--and the accepted formatsPlease send recomendations for resolution.