For iPhone, just slide the device to left, you will see Delete button. For Android, press and hold the icon for a while to delete it.

Hi, On the router's management page, you can go to Network---DHCP--DHCP Settings, then change the Primary DNS to your ISPs DNS server or 8.8.8.8, then Save and Reboot the router.

Did you have the feature on the router before you updated the firmware?

Hi, what's the modem number of your router? Did you setup the extender next to the router? We know that the wifi range of 5G is not as far as 2.4G, so try to setup when the extender is next to the...

The digits in the wifi name for the product is the last 4 characters of the MAC address, do you see MAC address at the label on the box? But you still need to check the label on the unit to know...

It is an invalid IP address. Try another device which is able to connect 2.4G to avoid it is a single device issue. And here is an new firmware for RE200. You may have a try....