My old Samsung Galaxy J7 SkyPro phone died, so I bought a newer Samsung Galaxy model (A11) to replace it. But the pre-loaded Samsung Messages app apparently won't let me send messages from that phone to my PC -- a Dell Inspiron 15-3567 laptop running Windows 10 and Thunderbird (currently version 78.12.0; as of this writing, I haven't downloaded 78.13.0 yet). I've been doing this for years with no problems -- sending notes, links to interesting articles and other Webpages, etc. to my PC so I could back them up, look into them, and sometimes save and/or share them. I don't do e-mail on my phone, never have, and don't want to -- and my contact info on the phone has only my e-mail address, not the phone's own number . . . so the phone shouldn't be getting confused and thinking it's sending to itself. I've downloaded two other messaging apps (Handcent Next and QKSMS) which had good reviews -- but the same problems keep occurring. Sometimes I can't send MMS messages to my Thunderbird account, either. I don't think this is a Thunderbird problem -- but there's a reason why I wonder if it might be. My PC had a ruptured (hard) disk a bit over a week ago. Best Buy recovered the data from it -- including the Firefox and Thunderbird profiles, which re-installed when I re-downloaded them (with no trouble as far as I can tell). But there are enough other little funky things I'm still trying to catch up with from that incident that I wonder if this is another one. And the fact that three apps are all yielding similar symptoms does suggest that the problem may not be with them -- unless they're all now doing something the same new way and blocking me from doing what I've been doing for years. Any help would be appreciated.