You are trying to use Chef's knife command. Every time you try to regenerate a key or delete a user, you get an error like this:
"ERROR: Failed to authenticate to https://continualintegration.com/organizations/contintnickname as contint with key /home/ec2-user/.chef/contint.pem
Response: Invalid signature for user or client 'contint'"
What do you do?
1. Log into the GUI for Chef Manage.
2. Go to Administration -> Users.
3. Find the user referenced in the error message (e.g., contint).
4. Highlight the user and go to "Actions" on the right and click on the sprocket/gear icon. Click "Reset key."
5. This will reset the key, but you'll get a private key to place where the client.pem file should be on the Chef server on the back end. Delete the contents of the client.pem file on the back end and replace it with the content of this newly generated key.