If gitkraken won't work make sure:

The ssh-agent is running and "$SSH_AUTH_SOCK" equals "$XDG_RUNTIME_DIR/ssh-agent"
(this is the known ssh-agent issue I've already solved).

Next make sure whatever you're cloning/etc from is in your ~/.ssh/known_hosts file
(if using ssh). Gitkraken may fail to do this automatically. ie for gitlab run:
```sh
ssh-keyscan -t rsa github.com >> ~/.ssh/known_hosts
```