Often, I have some issues trying to access my very own server via ssh. That happens a lot when electricity goes off - yeah, electricity goes off in the XXI century. So, to make the story short... I have found that RSA host keys are some what invalid. I then deleted the file /user_folder/.ssh/know_hosts and voila, I'm able to make connections again.
These notes are intended mainly for me but feel free to use them if you find them useful. I have many notes from way different topics, there is no specific one or correlation between them.