Mailgun (SMTP) + Craft I'm trying to set Mailgun up on Craft (Like we've done plenty of times before) but each time it keeps saying that the connection to SMTP is failing. 

The error I'm getting is:


  2017/03/29 09:54:13 [error] [application] Email error: SMTP Error: Could not authenticate.


I've checked https://craftcms.com/support/troubleshooting-email-errors#dealing-with-errors and error description is:


  “Use SMTP authentication” was checked, but the credentials were incorrect.


But I've double checked these details over 10x now and they are 100% correct.

Is there any other reason this could fail? We're using port 587 and tried other ports but no success. Even opening these ports on the server doesn't connect.

Where would the problem be... Craft, Mailgun or Server?
Craft is just passing on the error message it gets back when trying to connect with whatever settings it was given.

And we're using Mailgun ourselves (port 587) for sending emails on https://craftcms.com, which is a Craft install.

Make sure you're using smtp.mailgun.org as the host and that you've got the transport type set to TLS as well.