E-mails are not able to be sent successfully if the user has signed up using an e-mail address at a domain different than the domain the Mattermost server is hosted on.
I’ve validated all server SMTP configurations, as well as e-mail notification settings using the same user and e-mail address for all settings. I am using the STARTTLS setting with the SMTP server auth credentials configured, as well as connecting over port TCP 587.
When I test the connection, I receive the e-mail that my SMTP settings are configured correctly. However I had found that users were unable to reset their password, as the e-mails could not be sent.
While troubleshooting using a user with a gmail address, I found this error:
err=Failed to close connection to SMTP server."
When testing using my own user (of the same domain that I’m using to host the server), a password reset e-mail is sent correctly.
For environmental info, I am hosting this on an Ubuntu server using mysql on the back end, the Mattermost front-end on the same server, and I have nginx (also on the same server) handling SSL offloading as well as an 80 --> 443 redirect.
Any help / ideas would be appreciated.