I use a Google Cloud VM and every once in a while I switch back to my terminal and see my ssh session has frozen. When I then try to reconnect

```
ssh -v  -i ~/.ssh/key  user@host.domain

```

It shows this:

```
OpenSSH_7.4p1, LibreSSL 2.5.0
debug1: Reading configuration data /Users/UserName/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 53: Applying options for *
debug1: Connecting to host.domain [123.456.123.456] port 22.
debug1: Connection established.
debug1: identity file /Users/UserName/.ssh/ke> type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/UserName/.ssh/key-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4

```

So it appears a connection is established, but nothing else happens and I need to restart the VM. What does this mean?

I should note that I can `ping` the host with no problem, so it's not frozen or anything.