In-N-Out Challenge Help

Hello Dear Colleagues.
I have exhausted myself trying to figure our second flag… have ssh connected on C2-1 and C2-2 (prove: when i curl 127.0.0.1:8888 it responses with(<p>HELLOW WORDL</p>), and started a http.server listen on my machine, but when I try to ping from either C2 hosts, it says can’t reach…
Could you guys help me with it? what else should be done after reaching C2-2 to have the flag