I have archer vr 400 v3 for 2 weeks

The modem keeps getting disconnected time to time and the interesting thing is in addition to dsl and Internet light, wi fi and lan light getting off and after restarting the modem rhe problem still exist!

The problems getting fixed randomly by restarting many times and I don't understand why wi fi light getting off and how the problem getting fixed and happening again time to time!!

When lights turned off, 192 168.1.1 page usually doesn't open either 

Please help me with this issue...