Can't Send Some Email Using Entourage X and Exchange Server

[Rick Kiley]

I am unable to send email using Entourage X v.10.1.6 using Exchange
Server. Email using our company's URL works fine; email to URL's other
than our compay's doesn't work.

The error message I receive is: "A message in your Outbox could not be
sent using account "<name> Exchange Account." The server did not
recognize the recipients or the server refuses to allow you to send
mail. 5.7.1 Unable to relay for <name>. Error 5550".

Can anyone help?

 

[Mickey Stevens]

Go to Tools > Accounts, open your Exchange account, click the "Mail" tab,
click the "Advanced Sending Options" button, and toggle the option for "SMTP
server requires authentication". Click OK, and you should be able to send
mail.