First of all make sure that you are launching the game via GOG GALAXY 2.0.
Next make sure that the game and GOG GALAXY 2.0 are added to your antivirus/firewall trusted/exception list, please add the following files to them:
C:\Program Files (x86)\GOG Galaxy\GalaxyClient.exe
C:\Program Files (x86)\GOG Galaxy\GalaxyClientService.exe
Restart GOG GALAXY 2.0 afterwards.
If the above doesn't help please also verify game files by clicking on Customization button from the game's card in GOG GALAXY 2.0 > Manage Installation > Verify/repair.
If the issue persists, please create a support request.