Ok this is necro posting, but i do really suggest the clueless guys following this guide to first test they made the key thing work, then login and disable password logins...

I gave this guide to a windows noob and he locked himself out 3 times before getting it right lol.

FIRST: Test SSH login with a key, instead of password

THEN: Disable password logins

Just common sense... i never tought i will be writting this in a guide to setup a node for blockchain...