“Unable to use key file “…\id_rsa” (OpenSSH SSH-2 private key)” when authenticating with PuTTY [closed]
PuTTY cannot use keys in OpenSSH format. You need to convert your key to .ppk format first. For that, use PuTTYgen from PuTTY package. Run PuTTYgen; Press Load to load the private key in OpenSSH format; Press Save private key to save the private key in .ppk format