Error sending email, authentication required

Hi I have recently decided to invest a bit of time in installing ghost on a VPS to see how it works and then to create a site with it. Everything has been successful up until the point of inviting new staff via email. I have done a bit of research through other topics and forums and I can’t seem to find anyone who is having quite the same issue.
The current error I am receiving is:


Originally I was having another error which suggested I had entered the wrong username and password but now I just get this error, over and over again. I changed my email settings, purposefully put in the wrong username, password or port to see if a different error occurs like I was having before but this is the only error I get now.
My email settings are:

"mail": {
 "transport": "SMTP",
 "options": {
    "service": "Mailgun",
    "host": "smtp.mailgun.org",
    "port": 2525,
    "secureConnection": true,
    "auth": {
      "user": "user",
      "password": "pass"
    }
  }
},   

The only thing I can think of that I have not tried yet is reinstalling ghost since I have done some work on the site and don’t want to lose that. But I will try reinstalling if that’s the only solution available.
Cheers

Here’s the mailgun configuration I use that works:

 "mail": {
    "transport": "SMTP",
    "from": "Robot Overlord <from@example.com>",
    "options": {
      "service": "mailgun",
      "auth": {
        "user": "from@example.com",
        "pass": "heheh"
      }
    }
  }

I suggest trying this first, and then attempting to secure the connection

Doesn’t change anything, still the same error. My guess is that there’s something wrong with the installation since seemingly no matter what I change the error stays the same.

So I had the same problem what ended up being the issue is that I had to use a different port try changing it to port 465. Also you need to double check that you have your domain on the correct region Default is the US if you didnt change it . so if you domain is in the US the host will be smtp.mailgun.org if its the EU it will be smtp.eu.mailgun.org

Below is what I personaly have in the config ile

  "mail": {
    "from": "'Ghost Server' <ghost@example.com>",
    "transport": "SMTP",
    "options": {
      "service": "Mailgun",
      "host": "smtp.eu.mailgun.org",
      "port": 465,
      "secureConnection": true,
      "auth": {
        "user": "ghost@example.com",
        "pass": "PASSWORD"
      }
    }
  },

The installation being an issue, while possible, is usually not probable. Checking the obvious things, are you restarting your instance after making configuration changes?

The original config you shared had “password” as a key, instead of just “pass”.

The error reads “Authentication required” because according to mailgun, you hadn’t provided authentication (the pass field was missing).

Make sure that you run ghost restart in between all changes. After changing password to pass and restarting, you should in theory get a different error message if there still is one.

As has been said, reinstalling is unlikely to help, this is almost certainly a nuance of configuration.

Thankyou! It was just that I had it as “password” rather than “pass” and yeah I had been restarting inbetween updates to the config. So frustrating that I missed something so simple, but thanks!