SSH authentication failed, please provide another key- Acquia
I had this problem too with Dev Desktop 2.
It was my first time trying to pull an Acquia cloud site to local.
I generated a key, added my public key to my Acquia profile, but still kept getting Authentication errors.  

What fixed it for me was...
SSH into the server (little square next to the SSH path in dev desktop), then just close it.
I was then able to pull the cloud site to my local machine.