in the test email you set up this morning, did you enter a from display name? or leave that blank?
In the security assist behavior, you have the from display name set to "STG CMS", try leaving that blank.
Also, make sure the address you are testing with is not the same as the from address. many servers will not relay email messages if the from address is the same as the to address.
Make sure the top address is a valid address on your hosted domain.