Running a JMeter 5.6 load test to validate OAuth token refresh stability on Genesys Cloud US1. The objective is to simulate 50 concurrent application users refreshing access tokens via POST /v2/oauth/token. The test plan uses a Thread Group with 50 threads, ramp-up 10 seconds, and a loop count of 100. Each iteration waits 30 seconds before requesting a new token to mimic realistic session timeouts. After 15 minutes of steady state, 40% of the requests return HTTP 401 Unauthorized with the message “Invalid grant type or credentials.” The client ID and secret are verified correct and have full scope. Rate limiting is not the issue since the volume is low compared to API limits. The environment is Genesys Cloud US1, version 2024-10. Is there a specific limit on concurrent token refreshes per client? Or is this a known issue with the OAuth provider under load? Need help ASAP with this configuration. The JMeter log shows no network errors, just the 401 response. The request body includes grant_type=client_credentials and the correct client credentials. Has anyone seen this behavior during load testing? The system works fine with 10 concurrent threads. The issue starts appearing at 20+ threads. This is blocking our security compliance validation for single sign-on integration. Any insights into token refresh concurrency limits would be appreciated. Also, checking if there is a recommended pattern for handling token refresh in high-volume scenarios. The current setup uses a simple HTTP Request sampler with POST method. No additional headers are set except Content-Type: application/x-www-form-urlencoded. The response time is under 200ms for successful requests, but the 401 responses are immediate. This suggests a server-side rejection rather than a timeout. Please advise on best practices for token refresh under load.
This is likely a rate limit on the token endpoint, not a WFM issue. Check your client secret rotation or implement a jitter in your JMeter script to avoid hitting the 100 req/min limit.
The rate limit suggestion is valid, but for a 50-thread JMeter scenario, the 401 errors often stem from token expiration race conditions rather than pure throttling. When refreshing tokens in bulk, the old token might still be in use by a pending request while the new one is being issued.
Try adding a “Random Timer” or “Gaussian Random Timer” to your JMeter test plan. A fixed 30-second wait creates a “thundering herd” effect where all threads request refresh simultaneously. This spikes the load on the OAuth service.
Also, verify the token_type and expires_in fields in your previous responses. If the expiry is drifting, ensure your script handles the refresh_token immediately upon receipt. For legal discovery exports, we usually implement a retry mechanism with exponential backoff in our Python scripts. In JMeter, use the HTTP Request Defaults to set a 3-second timeout and add a JSR223 Post-Processor to log the exact error_description from the 401 response. This helps distinguish between rate limits and invalid grant errors.