Sunday: SSH error connection. Solved it, but why it has worked out?

Hi everyone! I am new in hacking and I am learning. I got an error on SSH on Sunday machine and I solved it using a specific parameter (I don’t want to spoiler more) There is some good Samaritan that want to explain me what was that error and why my solution worked out? Obviously in pm I will send you my solution to discuss about it. Thanks in advance :slight_smile: