I'm having a strange problem in macOS Sierra, when trying to connect a remote server via SSH.
I have a key, which I have created it without passphrase. I can correctly connect to the server using that key with Putty (Windows) and CyberDuck (Mac).
However, when I try to connect via SSH using the command line (
ssh -I path/to/key user@server) the system asks me for the passphrase.
Any idea what could be wrong? How could I connect with a key that doesn't have a passphrase?