As of the server move in spring 2019 none of us can ssh into the expo server unless we set up ssh keys which identify the specific machine we are logging in from.
You will need to ssh-keygen a key on your device, email the public key to someone who already has ssh access (Wookey, Paul Fox, Philip Sargent, Sam Wenham..) and follow their instructions.
If you are already a sohpisticated user of these things, you might like to look at How to setup multiple ssh keys.