Had similar issue, some time ago, with freecad . Turned out to be a store issue, but let me explain better.
It seems freecad Snap author decided on not allowing distribution to some territories (there’s a setting for this on the store) and, although I had been able to install FreeCAD earlier, I changed ISP and it turned out that IP ranges on this new provider weren’t mapped inside store, and so, I was unable to download it again (exactly same symptoms). See this thread. If that seems the case, maybe Daniel (@ roadmr) can help you, as he did to me.