I cannot connect to the remote computer.
Depending on the type of error message you see, here are several things you can try:
Not enough memory. Close your other programs, and then try connecting again. If the problem continues, restart your computer, and then try connecting again. If you still cannot connect, contact your network administrator or technical support.
Network failure. Make sure that your router is turned on (home networks only), the Ethernet cable is plugged into your network adapter (wired networks only), your computer's wireless switch is turned on (mobile computers on wireless networks only), and your network adapter is working. If the problem continues, contact your network administrator or the person who set up your network.
The remote computer cannot be found. Ask the administrator of the remote computer to verify the computer name, and make sure you typed the name correctly. If you still cannot connect, try typing the IP address of the remote computer instead.
Connecting a home computer to a computer on a corporate domain requires an intermediate step to ensure that the computers can communicate. One way to do this is to establish a virtual private network (VPN) connection to the corporate network. Another way is to use a Terminal Services Gateway server. If you have problems doing either of these things, contact your system administrator or technical support.
Connecting two home computers across the Internet is also possible. However, doing this typically requires detailed knowledge of the router configuration, port mappings, and IP addresses.
If authentication is enabled, you must type a full computer name (for example, Computer1.Example.com) on the General tab of the Remote Desktop Connection dialog box.
To find out what level of authentication is enabled:
Note: This information provided by Microsoft.