The customer said that he wants to set up a guest network on the ESR900. He has tried enabling the guest network function but the SSID field would be greyed out.
The customer has to first enable at least (2) SSIDs on the band that he wants to have the guest network to be on. The customer can even enable a guest network on both the 2.4GHz and the 5GHz band as long as he sets up (2) SSIDs on the 2.4GHz band and (2) SSIDs on the 5GHz band. The customer can set up the SSIDs on the basic wireless settings option on the 2.4GHz and 5GHz wireless settings pages.