Ghost Labs: Mailgun domain and API

Hello I am self hosting a ghost website.
I am experiencing some problems using Ghost Labs Newsletter feature.
When I set up my mailgun domain and API key the newsletter fails to send.

Here are the steps I took.

First: domain
API key: private API key
When I test the email from the post sidebar it says:
“Error sending mail, please check your Mailgun configuration”

Second: full api EU link
or domain:
From the post sdebar for test email it says “Email Sent” but the email does not really send and it does not reach the mailgun server either.

I tried using mailgun from command line with curl and it works so I am pretty confident that the url, API key and DNS settings are correct.

Here are my ghost configurations.

  • Version 3.2.0
  • Environment production
  • Database mysql
  • Mail Direct

Please, can you help me? Thanks a lot