Rock pi 3A getting unreachable state

I was working on Rock pi 3A board, installed with Ubuntu 20.04 version.
The issue I am facing is, the board is getting unreachable state after few secs (15 secs).
Using netplan I changed the IP configurations. and appear to be on different subnets.

Yes, is my pc ip and is board (rock 3A) ip, both devices are under same network. Is there any thing to do with services ?

What is your netmask?