netgear a6150

i can connect to 2.4ghz networks without problems. my wireless mode is a/n/ac, as said in the user manual for my adapter. my wifi's mode is 802.11ac, but i can switch it to n. bandwidth is 20mhz+40mhz+80mhz auto(the only one). channel is 40. i tried changing the ssid. my other devices connect...