GTX1080 multiple monitor blackout

[LEOMODE]

My mac environment is in my signature.

So I use 4 monitors with GTX1080. I wanted to mirror one HDTV and all monitors are blacked out.
I only tried to connect that HDTV but still no luck.

Is there anyway I can reset the setting for that particular HDTV, or go into Safe mode or something to put it back to factory default? Because every time I boot up my Mac OS, now I have to disconnect that HDTV, otherwise everything will black out.

Thanks.

 

[bsbeamer]

Connect only ONE monitor then follow this:
https://support.apple.com/en-us/HT204063

Then connect your other monitors.

For mirror with multiple monitors have found hardware solutions 1x2 HDMI like this work a lot better:
https://www.amazon.com/dp/B005HXFARS