Error Message 0x8008201c

I am unable to launch a game on GeForce NOW for Mac or PC and see the error message 0x8008201c.  How do I fix this?

If you are consistently seeing the error message 0x8008201c when attempting to launch games, a firewall or anti-virus program may be preventing a connection to our game streaming servers. Please contact your internet service provider (ISP) or network administrator and ask if they have any restrictions on TCP or UDP traffic originating from the network ports between 10,000 – 20,000. If the problem persists, check your anti-virus software to see if it supports real-time background protection. If it does , disable it temporarily. Once your anti-virus is disabled, make another attempt to launch GeForce Now. If GeForce NOW launches correctly, then this means your anti-virus software is incorrectly flagging the GeForce Now application which is preventing it from working correctly.

What to do if your anti-virus has flagged GeForce Now incorrectly:

• Update your anti-virus definitions
• Report the incorrect flag as a false positive with your anti-virus software maker
• Add exclusion to your anti-virus software for GeForce Now by adding the folder below.  
  C:\Users\(Your Windows Username)\AppData\NVIDIA
• Report false positive to your anti-virus software maker