unrouteable mail domain

[dp]

what does this mean?
Outlook worked just great until a week ago and now most messages get bounced
with an error saying"unrouteable mail domain"

 

[Lanwench [MVP - Exchange]]

what does this mean?
Outlook worked just great until a week ago and now most messages get
bounced with an error saying"unrouteable mail domain"

Contact your ISP/mail host and verify that you're using the right settings.

 

[Jeff Stephenson [MSFT]]

what does this mean?
Outlook worked just great until a week ago and now most messages get bounced
with an error saying"unrouteable mail domain"

What version of Outlook do you have? What is the exact text of the error
message you get? You might try enabling authentication to your outgoing
server, which can be done on the "Outgoing server" tab for your account.