There is a compliance issue with "resend this message" option in office 365.
If we use option "resend this message" for any email which we have received from any others. The new recipient received message from original sender only.
I received message from A and I (B) used option "resend this message" and send it to C the recipient C will not able to verify that the message is send by B as in his mailbox the from filed will show that it comes from A, however recipient can see it was send by A.
This will only work in the confines of your own organization, and assuming that you have the necessary permissions to send as/impersonate the original sender. Or your server is acting as an open relay, in which case you have bigger problems.