So I’ve got most of my GBZ sorted but..

I am running a 3.7v lipo with the Power Boost. But regardless if the lipo is attached or not... when the 5v USB lead is connected to the PowerBoost and I turn it on I just get constant Pi and Screen restarts... like there’s power issues but I can’t see the problem?
I have attached pics and a video of the issue. Any help would be awesome as I can’t continue to finish the build until I know this is working.
Thanks in advance all!
Video Link:
https://s14.photobucket.com/user/BigDa ... B.mp4.html