"rpc error: code = Unavailable desc = closing transport due to: connection error"

I am using k8 to host my grpc service.

Sometimes, I am getting the following error (few milliseconds into my request):

rpc error: code = Unavailable desc = closing transport due to: connection error: desc = "error reading from server: read tcp <ipaddr>:52220-><internal ip addr>:8070: read: connection reset by peer", received prior goaway: code: NO_ERROR

May I ask how will this occur? Could it be that the k8's network is down?