The detailed error message is as below:
Your computer can’t connect to the remote computer because your computer or device did not pass the Network Access Protection requirements set by your network administrator. Contact your network administrator for assistance.
Follow the below solution steps to resolve RemoteApp Disconnected error because did not pass the Network Access Protection requirements.
This RemoteApp Disconnected error happens because the server with Remote Desktop Role installed does not have the correct certificate or the certificate has expired.
Go to Server Manager > Remote Desktop Services > Collection > Task > Select your collection > Task > Edit Deployment Settings > Certificates > Check and reinstall each one as required.