BUG? ssh with key from Mikrotik to Cisco switch - error:0D078079:lib(13):func(120):reason(121)

[eguun]

To add on the key topic:

I generated keys on a macOS using the command from this post:
http://forum.mikrotik.com/t/importing-private-ssh-keys-fails/132243/1

ssh-keygen -t rsa -m PEM

Nothing really exotic