1. Restart your computer. Software conflicts may arise during day-to-day usage that causes a network error, thus provoking a NAT error. Restarting clears the system cache and may fix this error.
2. Close any networking devices and programs that use a heavy data connection. For example, bitTorrent clients such as Vuze or Azureus are notoriously common causes of NAT errors. If shutting down the bitTorrent file sharing software and similar network-intensive programs does not fix your NAT error, continue to Step 3.

3. Open your firewall software's preferences options. Check the level of security at which the firewall is currently operating. Some firewalls set a default security level that is too stringent and prevents legitimate software from accessing the network, thus causing NAT errors. Check that the firewall is allowing legitimate traffic and has not closed all of your computer's ports.
4. Reset your Internet or local network router. Use a paper clip or pen point to press the recessed reset button on the back of the device. Hold down the reset button for 10 to 20 seconds until all of the lights on the front of the router flash. Release the reset button and wait for your computer to reconnect to the network.