Warning - HTTPS has not been enabled as it is not available on this server. HTTPS connection test failed with the following error: HTTPS version of the site returned an invalid HTTP status code.

If you are running a Joomla web site and you have just tried to set the 'Force HTTPS' setting to 'Administrator Only' or 'Entire Site' and you receive the error below then we may be able to help.

Warning HTTPS has not been enabled as it is not available on this server. HTTPS connection test failed with the following error: HTTPS version of the site returned an invalid HTTP status code.

We've noticed the same error on a few of our sites recently and it is a combination of turning SSL on and using PHP 7.1.

For us, what had happened was that we had upgraded the site to use PHP 7.1 and then tried turning on SSL, that's when we received the error above.

To fix it, we downgraded the site to use PHP 5.6 then logged into Joomla and enabled SSL. This worked as expected. We then upgraded the site to use PHP 7.1 again.

Please try this and if you have any problems, just get in touch and we'd be happy to help.