Warning URL is unreachable

Here is the screen shot https://screencast.com/t/NzE3WI7oauC of the issue I couldn’t find a way just to turn off the warning which appears to be coming from Facebook. The plugin works if there is a patch to just stop the warning I’m good.

I just solved that issue on my website – the issue was that the URL I had not written the right URL in “Site URL” (https://developers.facebook.com/ > Apps > Settings). In my case I had written “https://website.com/” instead of “https://www.website.com/” – some people got that issue because they had forgotten to put the “/” at the end of the URL. After adding “www” in the Site URL in FB Dev, I had to wait for a few minutes and the issue disappeared.