SSH and local keys

I'm trying to secure some of my SSH connections with a certificate and for the life of me i can't get it to work with RDM...

I have the key in my .ssh folder, it shows up in the SSH key manager (local), it's loaded into the SSH key agent (not sure if this is needed, but i did it anyways), but no matter what i put for the options in the connection, i can't get it to connect, it just says


If i use PowerShell in windows, i can connect just fine.