a bit more detail would be very helpful. What did you mean with policy related error?
What version of servicedesk do you use? What kind of mail server is in the background. Can you send a test mail in the outbound mail settings?
First thing I would check is the eventlog, are there any errors with the outbound mail or the background engine?
Here is a link to a trouble shooting guide for first guidance:
I'm sure with a little bit more info you will get help here...
Ah...I've seen the other post that you opened for the same problem:
Could it be that your servicedesk server is not allowed to relay mails through your mail server? As far as I know an Exchange Server would not allow by default to forward mails from another mail source to a mail box.
You have to add your application server to the relay allowed list. This should be done by your mail admins.
Hope that helps