You could try the method in the answers provided in the threads below. They are rather lengthy so I shan't quote them. They involve using the Browser Console.

https://support.mozilla.org/en-US/questions/1281202 https://support.mozilla.org/en-US/questions/1305068

Thank you Terry. I looked at both of them but unfortunately neither addresses my specific problem. My issue may be related to the most recent Firefox update, which took place earlier today. As I said, I've used Gmail as my mailto account for some time. Today, the option simply disappeared.

Thank you Dropa for your reply. My Windows default MAILTO was Firefox. And in the Firefox browser mailto setting, it previously gave the option to select Gmail in the drop-down menu, but that option is no longer there, which is the problem. The link you suggested provides the instructions I’ve used to try to resolve it, but Gmail has disappeared from the options.

However, your question about my default mail program prompted me to change my Windows default MAILTO. I downloaded the app EasyMail (for Gmail) from the Microsoft store, set it as my default MAILTO, and that solved my problem.

I’m still puzzled why the Gmail option disappeared in the Firefox browser settings, but as a result of your question, I found a workaround. Thank you for your help!

EasyMail is a simple solution to this problem. You must first make EasyMail your Microsoft email default, then go to Firefox settings, where you will now find EasyMail as a mailto option.

Thanks lindabknight!

Thank you peterpangloss. That is what I did and it is working well.