BTW, try block tp-link, see if it works, some routers cannot control https websites

Did you refer to this link: http://www.tp-link.com.au/faq-561.html Make sure the system time is correct. Can you share the screenshot of your settings? Maybe there is some incorrect settings when you...

Will you lose connection if you connect to any other wifi on your iPhone 6s? Such as connect to your router's wifi directly? Windows PC works fine means the wifi is good.

All TP-LINK powerline adapters are compatible with each other:cool:

The RE650 supports Airprint. But your printer HP 8600 is not in the compatibility list for airprint: https://support.apple.com/en-us/HT201311 So it is hard to say if it is the problem on the printer...

You may refer to this link to find the password: http://www.tp-link.com/us/faq-399.html Normally they use WPA/WPA2, but you can choose WEP as well for security type.