@Kevin_Z Tried everything and it seems nothing works. Then I did two things that at last solved the problem. My ISP is planning on shifting to IPV6 which is still not implemented. So there was some...

@Kevin_Z It's the same. I have checked. I tried changing it to google dns. It's still the same. I have also disabled all securities. Nothing changes.

Bought an Archer C6 v3.20 (US) today. My ISP uses dynamic IP connection. So I have cloned the MAC of my previous router in this one. Everything is fine on all my devices. But one of my Amazon Tablet...