Check connections between the Wireless Router, the external power supply, and the wall outlet.
If the power indicator does not turn on when the power cord is plugged in, you may have a problem with the power outlet, power cord, or external power supply. However, if the unit powers off after running for a while, check for loose power connections, power losses, or surges at the power outlet.
If you still cannot isolate the problem, then the external power supply may be defective. In this case, contact Technical Support for assistance.