SMTP setting in self-hosted Ghost

Hi!

Version: 3.20 (self-hosted)

Im trying to configure Ghost to use my mail server in config.production.json.

My config:

"mail": {
    "transport": "SMTP",
    "from": "'example' <mail@example.com>",
    "options": {
      "host": "mail.example.com",
      "port": 587,
      "secure": true,
      "auth": {  
        "type": "LOGIN",
        "user": "username",
        "pass": "password"
      }
    }
  },

Ghost never tried to login to my mail server, i checked the logs.
It uses the direct mail sending, the config is irrelevant (as i see).

Other:
I used Ghost before, and there was a button to send test email in Labs. Where is this button? I test my configuration with invite email.
I dont think this is a good way to test.

The problem is solved!
How:

I revoked the existing invitations.
Firstly i send the test invitation with direct mail. This direct mail is binded to that invitation process (?).
Restarts doesn’t helped, but the revocation is solved.