If a radio has been reset they will default to factory settings (IP, SSID, etc.) and no longer work properly on the network.
If the radios are pointed directly at one another and the signal lights are off, try turning the radios away from one another and see if the signal lights come back on. If the signal strength is too high the signal lights will turn off. Pointing the radios away from one another will reduce the signal strength.
If the SSID on the access point (AP) does not match the one used by the client the radios will not connect and no signal lights will come on.
If the IP addresses are not on the same addressing system the signal lights will stay on (provided the client is locked to the MAC address of the access point (AP)) but there will be no way to access the client.
If the wireless security passwords do not match the signal lights on both radios will flash slowly, as the client radio locks to the access point’s MAC address and then gets booted by the wireless security.
If the channel widths on the radios do not match, the signal lights will turn off and there will be no connection.