Unable to enable secure SMTP connection.
Steps to reproduce
We are using Mattermost 5.18, until recently we were using non-secure SMTP on port 25, however starting in 2020 IT has disabled that option and we are only allowed to use SMTP with TLS 1.2 on port 587.
I expect the SMTP “Test Connection” to be Successful.
Instead what I see is the following error message:
Connection unsuccessful: Connection unsuccessful: SendMail: Failed to open TLS connection, tls: first record does not look like a TLS handshake