What should I do if the AP module does not register one or more SM's?

What should I do if the AP module does not register one or more SM's?

There are several plausible scenarios? that must be considered:

The color code of the SM and AP?s do not match. Verify that the color code on the AP configuration web page is the same as the color code on the SM's web page.

The SMs is not scanning the frequency that the AP is transmitting on. Verify on the SM configuration page that there is a check box next to the frequency that the AP is transmitting on.

The SM is trying to register at a distance farther away than the AP will allow. The user should verify that the on the AP configuration page, the max distance parameter is set to a number that is greater than the farthest SM will register from.
There is no clear LOS. Make sure that LOS rules and Fresnel zone is considered.