Is there a way to sort messages using the actual 'from email address' and not the name of the person sending the email? Have not been able to do this.

I doubt it. As the from is actually represented in the message in the form From: Mozilla Support Forum <no-reply@support.mozilla.org> I would guess hat any sorting sorts on the full contents of the header, not just the email address part.

However this addon adds some new columns. I have not used it, but you should be able to sort on any column by clicking on it so you might get what you want. https://addons.thunderbird.net/en-US/thunderbird/addon/full-address-column/?src=search

Thanks, I'll check it out.

In Settings/General/Reading & Display, Message List, select Email only, and then sort by From, in Table or Cards View.

Perfect. While the extension mentioned in the 1st reply worked, I much prefer no not use 3rd party extensions.