What type of keys (RSA, etc) are you using?
EasyMorph supports only a few key storage formats and specific SSH-related algorithms.
First, check this topic. You may need to change the private key format.
Also, ensure that your ssh server allows one of the supported algorithms.
I just got the server logs which showed that the port that easymorph was trying to connect was different to the one entered for some reason, (supposed to be port 7822)
No, EasyMorph does not change the port to a random number.
If the port were changed, you would not detect a connection attempt on your server.