Get successfully initiated connection:
Get-WinEvent -logname "Microsoft-Windows-TerminalServices-RDPClient/Operational" | Where-Object {$_.id -match "1102"}
Get trying connection (failed and successfuly):
Get-WinEvent -logname "Microsoft-Windows-TerminalServices-RDPClient/Operational" | Where-Object {$_.id -match "1024"}
More informations: https://jpcertcc.github.io/ToolAnalysisResultSheet/details/mstsc.htm
