Discourse doesn’t send activation mail to the admin user, but sends the test mail whenever i run ./discourse-doctor , and also delivers mail whenever i try to signup as a normal user.
I use mail gun, and have also checked the error log using tail shared/standalone/log/rails/production.log everything seems to work fine.
Have you looked at mailgun logs to check delivery to SES for the admin user? And the equivalent log at SES? Are you also hosting the SES domain on your mailgun account?