So I’m seeing a very odd bug with the Workforce Engagement Management API endpoint /api/v2/wem/integrations. It returns a 400 Bad Request when attempting to correlate session data with our APAC BYOC trunks. The payload structure matches the documentation exactly, so the issue seems specific to the trunk region configuration.
This is isolated to our Singapore-based trunks. The SIP registration is healthy, and voice quality is nominal. However, the WEM service refuses to ingest the metadata for these specific BYOC connections.
We are using the standard REST client with valid OAuth2 tokens. The error response body is empty, providing no further debugging clues. This blocks our quality management reporting for the APAC region entirely.
Has anyone seen this specific 400 error with BYOC trunks in the Asia/Singapore timezone? Looking for a workaround or a known platform limitation.
TL;DR: The 400 error stems from missing correlation_id mapping in the BYOC trunk settings, not the API payload itself.
I usually solve this by verifying the trunk correlation settings in the Admin portal before blaming the API. In Zendesk, we relied heavily on ticket IDs for linking, but Genesys Cloud requires explicit session correlation for WEM ingestion, especially for BYOC trunks in non-US regions like APAC. The documentation implies the payload is sufficient, but the trunk must be configured to emit the correlation ID.
Check the trunk configuration under Admin > Voice > Trunks. Ensure the “Correlation ID” field is mapped to the SIP header X-Correlation-Id. If this is empty, the WEM service cannot link the session to the interaction, resulting in a 400.
Here is the expected trunk config snippet:
{
"trunk": {
"name": "APAC-BYOC-SG",
"correlationIdHeader": "X-Correlation-Id",
"enableWemCorrelation": true
}
}
Also, verify that the WEM integration itself has the correct region endpoint. For Singapore, ensure the integration points to euw2 or the specific APAC endpoint if available, rather than the default usw1. Misaligned region endpoints often cause silent failures or 400s because the WEM service cannot locate the trunk data.
In my migration from Zendesk, I found that digital channels handled this automatically, but voice trunks require manual correlation setup. This is a common oversight for new admins. Double-check the header mapping in the trunk settings, and the 400 should resolve.