AWS Linux EC2 - Add Stable Remote GUI for remote connectivity

I have multiple AWS EC2 Linux instance where I have configured a GUI/remote desktop setup that I access from my Mac using a Windows/remote desktop application. The setup works fine initially, but after approximately **2 days, the remote desktop connection stops working**... (Budget: $30 - $250 USD, Jobs: Amazon Web Services, Graphical User Interface (GUI), Linux, Performance Tuning, Software Development, System Administration, Technical Support, Ubuntu, Windows Server)