Relaying messages

[Sharon]

Once someone has replied to my email I can not then send
another reply to them on the same email.

I am getting an error message 550 - error in relaying
message.

How do I stop this?

 

[Lanwench [MVP - Exchange]]

Check your SMTP server settings in Outlook - make sure you are set up to
authenticate to the server if need be - verify that settings are correct for
all accounts.