Netgear WN3000RP-200PES Universal Wi-Fi Range Extender - problem connecting from laptop

I have a Dell Inspiron 5370 which has the Qualcomm QCA9377 802.11ac Wireless Adapter. I have a TP-Link TL-WR841N 300Mbps Wireless-N Router in the other room. My earlier Thinkpad laptop used to get the wifi signals fine even in my other room. But the Dell couldn't. So I purchased the netgear Wifi Extender & set it up with the same SSID - so that the laptop seamlessly works when I move it across rooms. This worked fine for a month. But since then I am facing issues - my laptop tries to connect to the extender but fails & then goes back to connecting to the router whose signal is too weak & hence unusable. I have to turn the extender on 2-3 times & also disconnect/connect to the SSID 2-3 times on the laptop before it successfully connects to the extender. The extender is very close to the laptop so it's not a signal strength problem. All the lights on the extender also seem to be fine/same when it does connect to the extender & when it doesn't. I have even done a factor reset on the laptop but the problem continues.

 

I have latest firmware on both the wifi adapter & the extender. 

 

Is there a way, I can troubleshoot this further?