Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

Can you attach a screenshot?

• https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem
• use a compressed image type like PNG or JPG to save the screenshot

The problem is explained in detail... and I would need to take a lot of screenshots!

Hey, Is your question that why error messages start with an informal tone such as 'Oops'? If that is the case then the link below might help you in that. https://ux.stackexchange.com/questions/53211/why-do-we-use-informal-language-when-the-user-encounters-an-error-or-issue

You only need to post one or two screenshots to show whether this is a Firefox message or a message coming from the webpage, so we can see what this is about.

It comes from webpages, not Firefox.

I think the next question should be:

Why do Google error messages sometimes start with "Aw, snap" ?