Set up DKIM
If your sending domains already sign with DKIM, then this should not be changed. We will simply forward the DKIM signed messages along to the recipient.
If there is no DKIM signing, you can decide to either sign this on your sending MTA, or sign with Mail Assure. It is not compulsory to sign with DKIM, however it often helps to "authenticate" your senders as much as possible.