That isn't a Firefox issue but the site your using that is doing the popup. The site is whom you should contact about the popup issue.

''<p>led1830 [[#question-1473676|said]]</p>'' <blockquote>Constantly getting pop ups from TechRadar......... </blockquote> Are these small popups on bottom right corner of Firefox windows? if so then they may be Web Push Notifications from sites you have allowed to send you notifications. You can revoke these permissions. https://support.mozilla.org/en-US/kb/push-notifications-firefox https://support.mozilla.org/en-US/kb/push-notifications-firefox#w_how-do-i-revoke-web-push-permissions-for-a-specific-site