I have a user complaining about not being able to send emails using Windows Live Mail. She claims that everything was working fine and the problem started suddenly, without having made any changes. She’s in a different city from me, so I can’t go take a look.
The error message says:
The message couldn’t be sent because the server has rejected the sender’s email address. The sender’s email address was [her correct address].
Server error: 550
Server reply: 550.Access denied - Invalid HELO name (See RFC2821 184.108.40.206).
I translated the first part because she has the mail client in Spanish, so it’s likely not verbatim to what Windows Live Mail says in English.
I googled “invalid HELO name” and most articles said that the most likely error is failure to set up authentication on the client for the outgoing server. That wouldn’t start out of nowhere, but anyway, I sent instructions on how to configure the authentication. She says that the error remains, and that she even had someone more knowledgeable than her to take a look.
All other email accounts are working fine and I don’t have her account restricted or anything, so I’d bet this is a client error, but is there anything that could be causing this server-side? Or do you have any tips on what to do?