I, too, am running this app on 2 desktops and a laptop. Windows 7 and Windows 10. Having the exact same issues. No syncing across phone/pc. I can send from the pc, but not see replies except on my phone. My issue started in August. Please assist.
I also have the problem. Message+ on my Windows 10 laptop have not been syncing with my cell. Note this started when I replaced my Pixel XL (first gen).
I believe that the problem is related to Microsoft Store which kept me from updating Window 1903 version. I had Windows update marked to update other Microsoft products, like Office 365, but kept getting errors. Once I turned that Advanced option off, Windows updated. This does not fix Message+ but might give the Verizon software guys a hint. Bring back the old version not running through Microsoft Store.
Microsoft has made many security changes since the old version. Verizon should make necessary updates to the old non MS store version and get us a working module.
It is most definitely the app. My desktop was running the previous version of Message+ and work until August 31. Yesterday I Uninstalled the older version and reinstalled the 188.8.131.52 It worked flawlessly until the next day thrn stopped syncing. This is unacceptable for this big of company to write this poor of code!!!
Verizon has stated multipled times now in emails to me from customer support and also on this forum that they are no longer supporting Windows 10 with Message+. They also stated that we should use the web based verson on the verizonwireless.com website. Now I cannot even access teh web based version. I just get a spinning icon with it "connecting". No luck. Basically Message on anyting other the phone is jus tnot being pursued by Verizon as something to get working. Very disappointing for sure.
I've been using the site in the link you shared for years and it started acting fickle a couple of weeks ago. It receives messages, but most often will not send them, and constantly refreshes itself.