Can not get the device up after flash balena OS onto SD card

I followed this: HowTo: SSH into host device to ssh my device
but it shows:

ssh root@8b0f5ca.balena
Via vpn.openbalena.demo:3128 → 8b0f5ca.balena:22222
HTTP return code: 404 Not Found
ssh_exchange_identification: Connection closed by remote host

It seems there’s some problem on Internet connection
Should I directly login the device and run journalctl -f -a -n 1000?