Hey there!

Your problem isn't related to Firefox but Yahoo.

If you forgot your password, you should reset it. Please see the following links on how to do so:

https://help.yahoo.com/kb/SLN27051.html https://www.businessinsider.com.au/how-do-i-change-my-yahoo-password-2020-6?r=US&IR=T

Hope I helped!

Kind regards,

Bithiah

In the event that the passwords information is lost, you should record all information in a separate text file somewhere else on your hard drive, or written down. You can easily copy and paste if you need to do so. If you are concerned about someone else looking at that file, you can compress it using a password.