How come? AES is obviously the most popular encryption type. How come Samsung and iPAD have trouble with AES.... Have you tried the WEP encrytpion as well?

Which security type did you select? The WPA/WPA2-Enterprise on the firmware ?

I did as what descripted, I can access the USB model when my WDR4900 works as an Access Point Did you change the LAN IP address of WDR3600 to the same segment with the main router? Cause if your...

"concurrently " means both 2.4G and 5G can be connected for Internet. Not specifically means which one is being used. As for Phone , you can mess around with the wireless settings, like the channel/...

Check the gateway of your computer, that is the IP address of your router, you can use it to access router's web server

It seems your flash is burned with wrong firmware , did you install TP-LINK official firmware, not a DDWRT? You can try to hold the reset button on the rear panel for 10s to reset it, but I am not...