By default most browsers such as Google Chrome, Firefox, Internet Explorer and Safari block pop-ups. So, if your browser is blocking the Facebook pop-up you need to disable the pop-up blocker. 

How you turn off the pop-up blocker differs per browser, whether you’re on Window, Mac or a mobile phone.

Windows 
You’ll find instructions for most browsers here
https://www.isc.upenn.edu/how-to/configuring-your-web-browser-allow-pop-windows

Mac
This article describes how to disable pop-up blockers on your Mac:
https://www.digitaltrends.com/computing/how-to-allow-pop-ups-on-a-mac/

Safari
This article describes how to disable pop-up blockers for Safari on Mac and iPhones and iPadshttps://www.lifewire.com/manage-pop-up-blocker-in-safari-4136249

Android
This article describes how to disable pop-up blockers for Android
https://support.google.com/chrome/answer/95472?co=GENIE.Platform%3DAndroid&hl=en-GB