ngrok’s TCP endpoints are perfect for SSH traffic. Simply start a TCP endpoint to port 22 and you should be all set. 
ngrok tcp 22
TCP endpoints are only available on a free plan after adding a valid payment method to your account.
When connecting through the ngrok TCP address, make sure you specify the port separately. 
ssh -p PORT user@NGROK_TCP_ADDRESS
If you are getting any sort of failed connection, most of the time there is a misconfiguration with the server you are trying to connect to or the credentials you are using.