This has been an ongoing issue even with the previous version of the desktop app.  I just installed the Windows 10 version on my desktop and it still seems to be struggling to sync.  I can send messages from the desktop, but receiving them is hit and miss.  Sometimes it works and sometimes not.  The older desktop version also had message notifications that would pop-up when getting messages, but the newer version doesn't seem to have that.  I am pretty surprised the software took such a step back in functionality.  Hopefully they come out with a decent version soon.  I have been writing to support and in forums about the desktop messaging apps since it first came out, which I am guessing has been 5-6 years now.  I know there must be thousands of complaints, comments, suggestions.  Spend some of those profits on your people and give an app that works!