Please follow these steps to make sure we can fix the issue:
Title WorldCat.org (updated 20181128)
URL https://www.worldcat.org/
HJ https://worldcat.org
HJ www.worldcat.org
HJ worldcat.org
DJ worldcat.org
2. Exact error with screenshots of the error.
3. Client IP address.
4. Ray-ID (this is a piece of information sometimes present on the CloudFlare error itself).
5. How to reproduce the issue along with test creds (send the test creds through onetimesecret.com link).
6. Timestamp.
7. URL (of the error).
Please send the information to OCLC Support.
We will work on resolving the issue for you.