Last week I found out that the account name that you use in Azure automation are case-sensitive. We found this after a co-worker was adding a credential to the credentials assets. I had used some capital letters to read the account name a bit better in our local AD and my co-worker just wrote them down with small letters. He came back to me asking if the password was correct because the credentials did not work. After some tries and digging we found out that the casing of the account was the issue.
Be warned for this.
Repost from my company blog: https://worktogether.tech/2017/04/02/azure-automation-credentials/