How to give SQL Server Job Owner permission to Proxy a Credential I've created a Credential Cred1 (DOMAIN\USER1 with the secret = domain password)
I've created a SQL Agent job with owner to NT AUTHORITY\SYSTEM
The job needs to proxy as credential Cred1


So when I run the job it fails with the message that NT AUTHORITY\SYSTEM wasn't allowed to proxy 1 (I only have one credential) for CmdExec.


  "Unable to start the execution of step1 (reason: JobOwner NT
  AUTHORITY\SYStem doesn't have permissions to use proxy 1"


I've done a bit of google search for the permissions needed, and I read that I need to give operator access to the NT AUTHORITY\SYSTEM login in the MSDB. I've tried this but still no luck.
Expand SQL Agent
Expand Proxies
Find your proxy, right-click on it and choose Properties
Go to the Principals tab
Add the NT AUTHORITY\SYSTEM account  

This will give that account permission to use the proxy.