Sophos Firewll doesn't af DKIM information to outgoing messages

Trying to use DKIM on Sophos Firewall, XGS107 (SFOS 21.0.0 GA-Build169) and I'm stuck. I've been through some of the documents posted here, trying to apply some of the suggested solutions. Anny suggestions...
Sophos MTA/VPN/VPN-Portal/User-Portal etc. mit Authentifizierung am ADDS

Schönen guten Tag zusammen, folgendes ist mir grade aufgefallen. Wenn das ADDS nicht erreichbar ist, lässt der Sophos-MTA, Mails zum E-Mail-Server durch, an Empfänger die es gar nicht gibt! Dann antwortet...
XG MTA to Office 365 Connector “Empty Certificate”

I’m trying to move Office 365 connector authentication from IP-address to certificate. A Let’s Encrypt certificate has been created (on SFOS 21) and added to the SMTP TLS configuration under the Email...
Email Protection auto generated MTA Firewall Rule

Hi, I can't seem to find a clear answer as to why the auto generated MTA firewall rule is needed. As I understand it, in MTA mode emails are being 'handled' by the firewall rather than just traffic passing...
Define exception for email protection in MTA mode with *.outbound.protection.outlook.com

Hello, We are using onbox email protection with our SFOS 20.0.2, XG-System. I defined an FQDN-Host object as having the FQDN-wilcard *.outbound.protection.outlook.com. This object is listed correctly...