Networking - remote desktop connection

I have setup 2 pc which is to allow remote desktop connectio. they are in same domain.
I can only connect to 1 pc only. the other one show error message { connection busy }. But that PC are ready to logon. When I go to that PC. It work normally.

Which setting should i check?

thanks,
David

In Control. Panel / System/ Remote Settings you can set whether a PC allows remote connections and specify which accounts are allowed.

Set the 2 PC in same way. But only 1 pc can be remote access & logon screen appeared.

Here below the failed PC. I don't know what to do. 





Thanks,
David