Well, I have no insight on the specifics of Thunderbird's junk logic, but there are two things you can do:

- actively manage your junk filter by routinely setting what is and is not junk. Thunderbird is often criticized for its junk filter, but it relies heavily on user input. This site has some good info on the topic: https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages

- consider creating a filter for this person to always mark as 'not junk'

David,

I'm working on it, the article is super! Can I download the article to my computer?

Thanks. SweetTasha

If you use Firefox browser, just click File>save as... and Firefox will create two thing: an HTML file with the website name, and a folder with the same name. Click on the HTML file and the page will appear exactly as it does online. OR, if you have a PDF print utility installed, you can select File>print and select the PDF program.

David, You stated: if you have a PDF print utility installed, you can select File>print and select the PDF program. I don't get File>print in my browser. I'll troubleshoot the browser problem. It may have something like File>print but with a different label. Thanks for your help. SweetTasha

Then you must be using another browser, which probably has the feature but in a different location. Chrome, I believe, has it on upper right menu (three dots)

I was able to download it with Chrome. Thanks. SweetTasha

You can try marking these messages as "not junk" to train Thunderbird's filters to recognize them as legitimate. You can also check if there are any rules or filters set up that are automatically moving these messages to the junk folder.