Unable to connect SSH with APM to RPI 4 via Lipo battery

Hi all, I am using RPI4 and APM 2.8 and trying to configure to with MAVlink. Everything seems fine with the connection with SSH Putty when I connect my RPI with wall power source. However, when I connect my APM to Lipo Battery and power thru RPI via telem port, I keep getting error of “Network error: connection timed out”.

I dont understand why. Please help me out!! thanks in advance!!!

I’ve tried changing it to static IP address, but same results…

Not enough power to your RPI from APM telem port… You need external BEC direct to the RPI.

Hi I have connect UBEC, but however i still get the same error…