postmark config

• transactional stream
• port 587
• secure : false (not sure why)

ghost config file location

Approach A (Bitnami installations using system packages):

/opt/bitnami/ghost/config.production.json

which is in turn a symlink to :

/bitnami/ghost/config.production.json

content to add in the config file

[existing database section here]
...
"mail": {
  "from": "_signature_email_",
  "transport": "SMTP",
  "options": {
    "host": "smtp.postmarkapp.com",
    "service": "postmark",
    "port": "587",
    "secure": false,
    "auth": {
      "user": "_token_",
      "pass": "_token_"
    }
  }
},
...

restart services

/opt/bitnami/ctlscript.sh restart ghost
/opt/bitnami/ctlscript.sh restart apache

aliased to the shortcut script:

/usr/local/bin/restart-service.sh

bitnami official reference doc

https://docs.bitnami.com/aws/apps/ghost/configuration/configure-smtp/