WHMCS Connect Showing Refused to Connect

Symptoms

WHMCS shows Connection Refused when attempting to access via WHMCS Connect.

Description 

When you add WHMCS Connect, you attempt to access the cPanel area, which returns a Connection Refused error. We can verify the error via the browser's webmaster tools, such as Google Chrome's Developer Tools:

Refused to display 'https://hostname:2087/cpsesssess/?login=1&post_login=##########' in a frame because it set 'X-Frame-Options' to 'sameorigin'.

Workaround

Perform the following steps in WHM >> Server Configuration >> Tweak Settings on your server:

1. Log in to WHM.
2. Navigate to Server Configuration » Tweak Settings.
3. Set the Use X-Frame-Options and X-Content-Type-Options headers with cpsrvd value to Off.
4. Click Save.