Configuring RMAD Integration with On Demand Recovery returns the error message "Unexpected error, please try again"

A simple remote PowerShell session test using the account specified on the Azure AD Connect credentials can be done to confirm if PowerShell Remote is enabled.
If it doesn't work, PSremoting need to be enabled and the RMAD server need to be restarted.
Enable-PSRemoting (Microsoft.PowerShell.Core) - PowerShell | Microsoft Learn