Share button open up the same page in pop-up window

Could you post your site URL here, so I can have a look?

Here it is https://jamaicagetawaytravels.com/golfing-in-jamaica-golf-around-jamaicas-pga-rated-top-courses/

Thanks for the quick response

Could you check your settings under SEO > Advanced > Permalinks, and make sure this option isn’t activated?
https://i.wpne.ws/fZPX

Let me know if it helps.

It is deactivated as per this screenshot https://jamaicagetawaytravels.com/wp-content/uploads/2016/03/Capture.jpg

Thanks. Could you try to deactivate all other plugins, one at a time, and let me know if you find a conflicting plugin?
It that doesn’t help, it might be worth switching to one of the default themes, like Twenty Fifteen, for a few minutes to make sure the problem isn’t linked to your theme.

Let me know how it goes.