[keycloak-user] 400 error email test connection behind nginx proxy

I am attempting to setup the email notifications through keycloak and am getting a 400 error when I attempt to test connection. I looked at an older post and made sure my admin user has an email assigned to them. However, no matter which realm we use, test or master the same error occurs. The Debug output doesn't produce any useful either. We are running behind nginx with ssl termination.