Invalid Protocol

When you see this error it is usually because you have configured Screens Connect to use a different protocol than the one set in your saved screen.

Screens Connect

If you enable secure connections (SSH) in the Screens Connect preference window...

Screens Connect for macOS

1. Open the preferences window via the Screens Connect menu bar icon > Preferences...
2. Check if Use Remote Login is enabled

Screens Connect for Windows

1. Double-click on the Screens Connect System Tray icon for the preferences window to appear
2. Check if Use SSH Tunneling is enabled

Screens

If you disable secure connections in Screens Connect, then do the same in Screens. Screens should normally perform that operation automatically.

1. Open Screens
2. Go to your saved connection settings under Security
3. Check if Use Secure Connection is enabled. This setting should be the same as in Screens Connect (on or off)