retrorealms: I did not have CryptoPrevent installed, I had all the right permissions and exceptions set up in both my firewall of choice and the built-in Windows firewall, I had not installed anything after installing GOG, and the first few days GOG worked fine until the first GOG notification triggerred this issue and simply would not go away...

When it happens, it looks like you can ignore it - as long as you don't close the error notification box, GOG will run seemingly fine but it's still a nuissance even if that's the case...

I tried manually starting/restarting the GOG services, I manually reapplied all the firewall permissions and exceptions, I uninstalled and then reinstalled GOG - to no avail...

The solution? Turns out the GalaxyCommunication service fails if connection attempt is made through my VPN. I had configured exceptions in my VPN for all GOG executables but for some reason the exceptions are sometimes not applied so GOG went through the VPN. By simply disconnecting and reconnecting my VPN, the GOG exceptions were reloaded and GOG now works just fine!