SMTP -test connection- button incorrectly gives username / password error.

Summary:

When trying to setup SMTP from Mailgun.org within JIRA, even if you enter the correct username and password the test connection button will return an error.

If you ignore the error and add the SMTP server it will work fine.

This is confusing for customers.

Steps to Reproduce:

• Add a custom SMTP server

smtp.mailgun.org
port: 25
username / password in comment

• press test connection

Expected Results:

Test connection successful message should be displayed.

Actual Results:

Red error message is thrown.