Battery replacement gone wrong

I have attempted to do a battery replacement, the first time I did this I was successful.

The screen was replaced recently and I was able to see the screen turned on and worked.

I have now reattempted another battery replacement but the device doesn’t turn on. The solder connection looked fine and I tried with a new battery but nothing happens now.

I read somewhere I might need to short the 3rd connection point to ground. Can someone advise how I need to this or any better suggestions please.

this a picture of the board