N300 Wifi Extender keeps disconnecting

What router are you using?

Is it loosing connection back to router or from extender to devices? The link lights will show you.

There's troubleshooting in the back of the manual for it. I'll link to the support site. Here's what I'd try though.

1. Wireless channels. the 2.4ghz signals travel further than 5ghz and has less available channels. Try changing channels on the router/extender to see if it helps. 

2. Try moving it. Sometimes hvac or foil lined insulation can be blocking signals. Moving it to a different outlet or different room can make a big difference. Try closer and further away. 

3. Reinstall firmware and try a factory reset. Sometimes firmware can get currupted. A reinstall and factory reset can help resolve this. 

https://www.netgear.com/support/product/EX2700.aspx

Here's a direct link to troubleshooting extenders.

https://kb.netgear.com/25731/Troubleshooting-NETGEAR-WiFi-Range-Extenders