With soap calls coming into Service Catalog from ITPAM, there were a few userids with the first character in upper case, so those soap calls were failing.
Service Catalog 17.x
On the Administration -> Configuration -> User Defaults tab, changing the setting of "User Id is case-insensitive at login" from "No" to "Yes" resolved the problem. The change should take effect immediately. Restart of Service Catalog is not required.