We have Discourse running fine. It’s at domain discourse.jackrail.space. Mails go out fine, and all users can send replies by email OK. Except just one user. The Reply address he is getting in his mailer is the domain jackrail.space not discourse.jackrail.space.
I am utterly baffled as to what/who/where is causing this address rewriting. It’s a showstopper to our site for various reasons.
I am using Amazon SES but I am fairly confident the problem does not lie there, as all the other users get the right reply address.
Has anybody ever seen anything like this before?