Getting 401 Unauthorized right after token refresh due to clock skew?

NICE CXone API & Integrations
1

Hey everyone,

We’ve been running into a weird issue with our integration that handles OAuth token refresh for Genesys Cloud. Everything works fine initially, but once we hit the refresh endpoint, the new token gets rejected immediately on the next API call.

Here’s the flow:

  1. We get a 401 on a standard GET request to /api/v2/flows.
  2. Our code catches it, hits the /oauth/token endpoint with grant_type=refresh_token.
  3. We get a new access_token back.
  4. We retry the original GET request with the new token.
  5. Boom. 401 Unauthorized again.

The error payload from Genesys just says "error_description": "The access token provided is invalid." but it’s definitely the token we just got back. I’ve verified the token structure in JWT.io and it looks valid.

I suspect it’s clock skew between our app server and the Genesys auth servers. Our server is in US/Eastern time, and I noticed the exp claim in the new token is sometimes a few seconds in the past relative to the server time when the request is made. If the server clock is even slightly ahead of the auth server, the token might be considered expired before it’s actually used.

Does anyone have a code snippet or best practice for handling this? Should we be adding a buffer to the local clock before making requests, or is there a specific header we need to send? We’re using the Python requests library, so it’s just standard HTTP calls.

Here’s a rough snippet of the retry logic:

def api_call_with_retry(url, headers):
 response = requests.get(url, headers=headers)
 if response.status_code == 401:
 new_token = refresh_oauth_token()
 headers['Authorization'] = f'Bearer {new_token}'
 response = requests.get(url, headers=headers)
 return response

Any ideas on how to debug the exact time difference or force the token to be valid? We’re losing a lot of data during these retries.

2

Clock skew kills tokens. Genesys rejects anything >5m off. Sync your server time.

ntpdate pool.ntp.org

If that’s clean, check the exp claim in the JWT. It’s likely expiring before your code uses it.