Can't connect to internet...

I bought the r6700ax wireless router and successfully went through the installation/setup using the night hawk app. However, the r6700ax will only allowed/connect my phone (the android phone I used for the installation)  to the internet but not any other devices. I could not connect my Amazon fire stick even though the sign in using the correct password was done. So I did a reboot of both the cable modem and the r6700ax. Still. Only my phone was (allowed) to connect to the internet but not any other devices. Please advise.  Thank you.