I have been using Firefox for many years without any problems. I’ve changed nothing on my laptop, but now, when I try and send an email, I get an “Unknown Identity” message. If I use my phone, everything works OK and I get no messages – it’s only on my laptop. See images of the messages attached. The location code in the message changes when I try and send another email. I’ve tried re-entering my mail server account details but problem still exists. Same thing if I try and add a new email address. I am not exactly computer-savvy and I have two questions: 1. What has happened (or what have I done) to create this problem? 2. How can I resolve this?

Thank you