PeerTube does not start if SMTP server is down

[gramakri]

Describe the current behavior

If the SMTP server is down, peertube does not start.

Steps to reproduce:

1. SMTP server down
2. Restart peerTube
3. PeerTube does not start

Describe the expected behavior

PeerTube can log an error on startup

Additional information

This was discovered on PeerTube package on Cloudron but it applies to all deployments. In the case below, it was an authentication failure.

Logs:

[pt.cloudron:443] 2020-12-11 19:29:03.949 info: Testing SMTP server...
[pt.cloudron:443] 2020-12-11 19:29:03.990 info: Connection established to 172.18.0.5:2525 {
  "component": "smtp-connection",
  "sid": "u8aWDNRV4Yw",
  "tnx": "network",
  "localAddress": "172.18.18.229",
  "localPort": 54806,
  "remoteAddress": "172.18.0.5",
  "remotePort": 2525
}
[pt.cloudron:443] 2020-12-11 19:29:05.011 info: User "pt.app@cloudron" failed to authenticate {
  "component": "smtp-connection",
  "sid": "u8aWDNRV4Yw",
  "tnx": "smtp",
  "username": "pt.app@cloudron",
  "action": "authfail",
  "method": "PLAIN"
}
[pt.cloudron:443] 2020-12-11 19:29:05.015 error: Failed to connect to SMTP mail:2525. {
  "err": {
    "stack": "Error: Invalid login: 535 5.7.8 Authentication failed\n    at SMTPConnection._formatError (/app/code/server/node_modules/nodemailer/lib/smtp-connection/index.js:784:19)\n    at SMTPConnection._actionAUTHComplete (/app/code/server/node_modules/nodemailer/lib/smtp-connection/index.js:1523:34)\n    at SMTPConnection.<anonymous> (/app/code/server/node_modules/nodemailer/lib/smtp-connection/index.js:550:26)\n    at SMTPConnection._processResponse (/app/code/server/node_modules/nodemailer/lib/smtp-connection/index.js:942:20)\n    at SMTPConnection._onData (/app/code/server/node_modules/nodemailer/lib/smtp-connection/index.js:749:14)\n    at Socket.SMTPConnection._onSocketData (/app/code/server/node_modules/nodemailer/lib/smtp-connection/index.js:195:44)\n    at Socket.emit (events.js:310:20)\n    at addChunk (_stream_readable.js:286:12)\n    at readableAddChunk (_stream_readable.js:268:9)\n    at Socket.Readable.push (_stream_readable.js:209:10)\n    at TCP.onStreamRead (internal/stream_base_commons.js:186:23)",
    "message": "Invalid login: 535 5.7.8 Authentication failed",
    "code": "EAUTH",
    "response": "535 5.7.8 Authentication failed",
    "responseCode": 535,
    "command": "AUTH PLAIN"
  }
}