DKIM-Signature: missing from header

spf/dkim/dmarc are appear to be all setup up on my dns. I can currently send and receive messages with out issue, both to hosted and non hosted mxroute emails. However;

when sending from mxroute email account to outside email… I can see the dkim signature in the receiver’s header.

when sending from mxroute email account to another mxroute email there is no dkim signature in the receiver’s header.

Is this a setting issue I need to correct or dkim is stripped/not used when sending to other mxroute accounts?

I found it the issue as I will be moving to more strict dmarc settings and was looking at the headers to check alignment before implementation.

The DKIM signature is indeed part of the remote transport in the exim config. If sending between users on the same server you won’t see it as the email never crosses that path.