Hi, just in case anyone else had this problem, I want to share what solved it for me!
The API email sending was working, but not the transactional email (error message: “Failed to send a magic link email”).
I tried every combination of mail { } values in the config.production.json … but it was a bug on Mailgun’s end.
Basically I had to create a new SMTP user (not the default postmaster@mg.example.com), and give it a manual password. Then it worked.
Hope this helps someone else :)