Lessons learnded part 3291: SSH error "permission denied (public key)", seems to have an obvious reason, I thought when a colleague asked me on supporting him. I explained how to generate public/private keys, how to put it to gerrit etc. Nothing worked. After 4 hours of sweat I found the error. He registered on Gerrit, was in the correct group, but had no username. It seems that the username in gerrit is NOT mandatory. However it's not possible to push via SSH without providing the user the public key should work for.