WEM API 400 Bad Request when syncing BYOC trunk idle times

I’m completely stumped as to why the Workforce Engagement Management API is rejecting our bulk update requests for agent availability states. We are attempting to sync idle times derived from our 15 BYOC trunks in the Asia Pacific region to ensure accurate forecasting. The payload includes the correct loginId and availabilityState, yet we consistently receive a 400 Bad Request with error code invalid_payload_structure.

The issue appears specifically when the JSON body exceeds 500 entries. Smaller batches process without issue. We are using the Python SDK version 1.3.4 and have verified that the OAuth2 token has the necessary wem:agent:write scopes. The timestamp formatting follows ISO 8601 strictly, and we have double-checked that the agent IDs match the internal Genesys Cloud identifiers.

Is there a known limit on the number of objects per request for the /api/v2/wem/agents/availability endpoint that is not documented? Or could this be related to a regional latency issue affecting the APAC tenant?

This is caused by a mismatch in the availability state enum values. The WFM API expects specific string literals like available or onbreak, not custom trunk status codes. Check the documentation for the exact payload structure required for agent presence updates.

Try updating your JSON body to use the standard Genesys Cloud availability states. Here is a working example:

{ "loginId": "12345", "availabilityState": "available" }

Ensure the timezone offset in your bulk request matches the agent’s configured schedule.