You may have an ssh agent set up that is trying to do private/public key authentication. If so, you can force SSH to use password authentication by adding:
`-o PreferredAuthentications=password -o PubkeyAuthentication=no`
to the SSH command.
For example:
ssh -o StrictHostKeyChecking=no -o PreferredAuthentications=password -o PubkeyAuthentication=no vagrant@1.tcp.ngrok.io`