What version of Firefox? What OS? Show evidence of the issue. Provide steps to replicate. What security software are you running if windows?

The version of Firefox and OS is in the attached jpg file. The security software is: Anti-virus: Sophos Endpoint Agent 2022.2.2.1 Not sure how to show the evidence of the issue because the problem shows itself in my private accounts: Myfitnesspal: I log in, whilst in the software I select a particular food from the directory but when I click to add it to my record I get the following error message. Page not found Sorry but the page you requested was not found. Please check the URL and try again.

Ocado: I received an email with an auto link (URL) to a survey the new tab just sat there with a spinning wheel.

National Savings and Investments (Premium Bonds): The site just does not work with Firefox.

All of these options used to work with Firefox but are now showing issues. All do still work with Microsoft Edge first time which suggests something has changed within Firefox.

Some sites are Browser specific for security checks and to access their site. So you should consult with the site webmaster of their site to be sure what Browser they approve to access their site. Firefox is general purpose site and I've seen sites aka eBay what is displaced in Chrome doesn't show up in Firefox. Edge from my usage seems to be more in-line with Business financial sites for their security purpose and if that is the case then you don't have a choice what Browser to use but to use Edge for logins.