You will receive the following error “Your session has ended because of an error: Error Code 0x4” whenever your Mac goes to sleep.
Since this is actually not a problem, please use the following steps below to mitigate this issue.
1: Launch a new RDP connection or
2: Simply increase the maximum outstanding connections limit on the windows client machine. The following DWORD registry key controls this value. See the following hyperlinks for what is Registry Editor and how to access the registry hives and how to search through Windows Registry.
Launch the Windows registry and navigate through the following hives
Computer\HKEY_LOCAL_MACHINE - SYSTEM - CurrentControlSet - Control - Terminal Server - MaxOutstandingConnections
Now create the DWORD key if your machine doesn't have it. - Set it to 10,000 (hex value)
I hope you found this blog post helpful. If you have any questions, please let me know in the comment session.