I am told to disable pop-up blockers in order to have a payment verified. I do not know what pop-up blockers are, I do not know where they are. When I go to Settings and search for pop-up blockers, I am told "Sorry! There are no results in Settings for "pop-up blockers"; and instructed to visit Firefox Support. I have been sent on this circular quest three times now. Please help me.
On the main menu, try going to Tools -> Setting's -> Privacy & Security and look for the Permissions section. In that is a checkbox for Block pop-up windows. You can uncheck that to turn that off globally or use the Expections.. button to the right to add the website you want to allow pop-up windows on.
When using the Search settings option, looking for just pop or pop-up should show that setting.
Tools did not get me those choices; but Settings > Privacy & Security was able to take me to a section for Permissions which had Block Pop-up Windows and Exceptions. Thank you, I hope this does it. Also thank you for the search suggestion.
A ribbon is normally shown at the top of the page when a popup is blocked, if you don't see this then it may be one of your extensions that is doing the blocking.
Does it still happen in Troubleshoot Mode?