The requested channel is already being added or removed from this service instance concurrently with another API request. The last request will be rejected to avoid inconsistent state.
Possible Causes
You might be adding a new channel to the service instance while the channel with the same unique name is being removed from another thread.
You might be submitting multiple concurrent requests to add a channel with the same unique name to the service instance.
You might be submitting multiple concurrent requests to delete the same channel by SID or unique name from the service instance.
Possible Solutions
Implement an operation retrier and repeat the failed channel API requests after an interval of time, using an exponential backoff algorithm.
Review your application logic that caused the race condition when adding or removing users. Perhaps the conflicting operations are happening in a loop that could be avoided.
Serialize your API requests that add or remove channels. Wait until the original request completes and returns an API response, before sending any successive channel requests.