Question monitor wont got past 60 hz

[lolongamer1]

so i recently bought a second monitor that was advertised as a 144hz gaming monitor. it worked fine for the first month or so and suddenly it wont go highen even with the other 60 hz monitor unplugged. i use a regular display port cable. sorry for the bad spelling and thanks in advance.
PC Specs:
i7 6700
gtx 1070 8gb
16gb ram

 

[LordVile]

Have you checked the display properties and nvidia control panel?

 

[lolongamer1]

In nvidia control panel i cant raise the refresh rate more then 60 hrz.

 

[Glenwing]

Please follow the steps in section 6.1.2 here first: https://forums.tomshardware.com/threads/how-to-connect-to-a-120-hz-display.3268285/