Having grey screen issues with CVAD 2203+ and higher on Windows Server 2022 Terminal server? I had this issue occurring on Citrix 2212. Try running this script. It might help you out. Do a VM backup or snapshot before running the script, just to be sure.

$iddHwId = “VEN_5853&DEV_1003”
$pnpDispDevPath = “HKLM:\SYSTEM\CurrentControlSet\Enum\SWD\RemoteDisplayEnum”

try
{
    $iddDevEntries = Get-ChildItem -Path $pnpDispDevPath -ErrorAction Stop| Where-Object Name -Match $iddHwId
}
catch
{
    Write-Output “Failed to query remote ID device entries”
    Write-Output $_
    return
}

if ($iddDevEntries.Count -eq 0)
{
     Write-Output “No remote ID device entries found.”
     return
}

$iddDevEntries | ForEach-Object {
    
    $devName = ($_.Name -Split “\\”)[-1]
    
    try
    {
        Remove-ItemProperty -Path $_.PsPath * -ErrorAction Stop
        Write-Output “Cleared values for $devName”
    }
    catch
    {
        Write-Output “Failed to clear values for $devName”
        Write-Output $_
    }
}

This saved my day:

https://discussions.citrix.com/topic/417832-cvad-connectionfailure-after-install-ltsr-2203-cu2-on-server-2022/page/3/