@Jack Jin (Qurate Contractor), Thanks for the reply. From your description, I know the affected Cloud PC is Windows 365 Frontline. In fact, Frontline Cloud PCs can't be accessed directly from Remote Desktop app. Instead, you can use the Windows 365 web portal if you want to access your Frontline Cloud PC. Your understanding is correct. This is the reason for our issue.
https://learn.microsoft.com/en-us/windows-365/enterprise/introduction-windows-365-frontline