authentication required for sending out emails
Hi,
I am using SDP to send emails and when I send to a group this error comes back.
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.
#550 5.7.1 RESOLVER.RST.AuthRequired; authentication required ##
Can somebody help please.
I am using SDP 7.6.1
Many Thanks
Martin