Hi,
I hope this request is within scope - please let me know if it isn’t.
I have the following setup:
1. The macOS Mail app is used as the local mail client.
2. Mailcow is configured as the incoming mail server.
3. Postmark is used as the outgoing SMTP server.
This configuration works flawlessly for sending and receiving mail.
I’m also using GPGTools, which provides a Mail app “Extension” that enables signing and encrypting emails using OpenPGP keys. In the Mail app, I can toggle signing and encryption via icons (a lock for encryption and a seal for signing).
When I send a signed email (to myself for testing: from postmarkapp/mailcow mail to a gmail):
• It displays correctly in my local inbox as signed/valid (both in the sender and receiver part)
• However, when I view the same message in SOGo (Mailcow’s webmail interface) after replying to it, or in the “sent” box, the signature appears as “invalid”.
I’m trying to understand why SOGo flags the signature as invalid.
Any insights or directions would be appreciated.
Thanks in advance!