### Answer This error indicates that your knowledge base is currently being updated by another API call, and you're attempting to make a concurrent modification request. What's happening: The knowledge base processing is not instantaneous—when you add sources, the status goes through states like

in_progress

,

refreshing_in_progress

, and eventually

complete

. [(1) ]() How to resolve: 1. Wait for the current operation to complete – Before making another API call to modify the same knowledge base, check that the

status

field has returned to

complete

. 2. Implement sequential processing – If you're adding multiple sources, queue your requests and wait for each one to finish before starting the next. 3. Check the knowledge base status before making update calls. The status values are: -

in_progress

– being processed after creation -

complete

– ready for modifications -

error

– processing failed -

refreshing_in_progress

– currently being updated This is expected behavior to prevent conflicting concurrent updates to the same knowledge base, not a platform-wide rate limit issue.

​ To learn more, see the sources I considered: [[1] Add Knowledge Base Sources](https://docs.retellai.com/api-references/add-knowledge-base-sources) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.