You are trying to connect your remote node via ssh. So make sure you have created remote directory on that node. Whenever Jenkins will run a job in remote node, it will create workspace on that node. For that you have to specify your remote directory name in node configuration .
Another thing to be noticed when we try to login with SSH, it will ask permission. So you have to set your Host Key Verification Strategy with Non verifying Verification Strategy in node configuration.
So you have to set these above configurations in your node and then try to launch your node.