Dead p40pro+ after disconnecting battery ribbon

I tried to switch off phone which has damaged screen so I simply disconnected battery ribbon from the board. Now, after I reconnected it the phone doesn't switch on. Also after I connected mouse to the phone it doesn't get any power. Normally the LED should light up, even when phone is off. Any help?

Is it normal for battery or mobo to fail in this type of case? I mean just when the ribbon was disconnected when phone was on. I was very delicate. I'm sure I didn't break ribbon cable nor fused anything nor broke the connector/jack.