Office Outlook from System Administrator - Undeliverable

[TRS]

At random receive a message when replying to a received
email"553 sorry, that domain isn't in my list of allowed
rcpthosts(#5.7.1)
How do I overcome this problem?

 

[Diane Poremsky [MVP]]

the server the person you are sending to is blocking your mail for one
reason or another. You can't do anything, except use a different SMTP
server.