@hendrikvl said in sender rewriting when using external SMTP:
And no, my mail relay does not accept IP whitelisting. It's not a proper mail relay service to be exact, but just a regular mail service with outgoing smtp for authenticated users.
Ah yes, someone was trying to do this with a gmail account as well sometime back (and more recently with a mailbox.org account). I think we have to implement this feature in Cloudron to make this use case work.