Lenovo A2010 keeps disconnect from WiFi extender

[anon(8716935)]

Hello, I have a Lenovo A2010 running the latest firmware version but I'm facing a problem with my WiFi extender. When I sit down a search on the internet while being connected to my TP-LINK TL-WA854RE extender it suddenly disconnects and it can't connect back again, its says problem checking identity. I've default reset the extender, modem and hard reset phone but the problem still remains. When I'm connecting directly through the modem I don't have any problem. I don't think the problem is the extender because my laptop and any other phone on the house connects without any problem.

Thank you for you time.