We added a new domain to our Exchange server. Users receive email both internally and externally. However, we created a group for orders, added exchange accounts to the group and assigned the group an email address (e.g. email@example.com).
When sending test emails to the orders group we received the following error:
Received-SPF: None (xxxxxxxExc.xxxxxxxxxxxx.local:
firstname.lastname@example.org does not designate permitted sender hosts)
When we googled this, it pertained to the Sender ID function of the Anti-Spam. Just for testing purposes we disabled the Sender ID function and attempted the test email again.
Received message : "Your message wasn't delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator."
#< #5.7.1 smtp;550 5.7.1 RESOLVER.RST.AuthRequired; authentication required> #SMTP#
This only occurs when sending to the group email.