Question / Problem
When SmartPOP2Exchange send messages to our Exchange Server we get the error:
"The smtp server answered: client does not have permissions to send at this sender." or "Sender denied "
What does this mean?
Answer / Solution
Since Exchange Server 2007 the exchange checks if the user of the authentication details used for the SMTP connection has the privileges to send mails using the address of the FROM field in the message.
With Exchange Server 2007 and newer you should NOT use authentication for the SMTP account settings in SmartPOP2Exchange.