This is most probably a mis-configuration on my part but I am unable to encrypt outbound
emails. I have generated an SSL email cert, via Comodo, and have imported it fine into
Djigzo. I have set a Force Encrypt Signature and the cert is selected, inherited green, on
the encryption certificate screen. Now when I send an external email I receive straight
away an automatic email saying "The message could not be encrypted". What am I
doing wrong ?