Hi @vballance,
The 401 Unauthorized response suggests that the error message is telling you that your username and/or password are wrong. Have a look at the CrossRef plugin configuration in OJS and double-check your credentials; since they suggest that there might be problems with upper-case usernames and passwords, try exploring that. OJS will just give CrossRef the credentials you supply them, without changes.
Regards,
Alec Smecher
Public Knowledge Project Team