My company recently moved to an outsourced our e newsletter distribution. Now we are receiving
Rejected-Message SMTP Error(504 MAILFROM is spoofed.) from our Tumbleweed mailgate.
How can I configure the mailgate to allow these messages through?
I hoped adding the appropriate values to our SPF record would do the trick, but it didn't. The source IPs the email is originating from is definitely included in the SPF record, and the record has propagated to the local DNS servers.