Is this issue occurring only on this particular AP? Do the devices connect fine to other APs in another location?   I had a similar issue, but with chromebooks, and I couldn't figure out what was going on.   What I did was change the radio settings on the SSID from 5Ghz only to Dual band with band steering, and for some reason that seemed to fix the problem. All of a sudden the chromebooks were able to see the SSID and connect, so something you could try on your SSID that is giving you trouble. ... View more