# knock.workflows.deleteSchedules throws UnprocessableEntityException: schedule_ids(cast): is invalid
## What's going on
Calling `await knock.workflows.deleteSchedules({ schedule_ids: ['YOUR_SCHEDULE_ID'] })` with @knocklabs/node 6.1 throws `UnprocessableEntityException: The following errors occurred: schedule_ids(cast): is invalid` (HTTP 422), even though the schedule IDs are valid strings. The same cast error appeared for `deleteSubscriptions` recipients. The payload shape matches the documented API.
## The verified fix
This was a library bug: the SDK was not sending `Content-Type: application/json` on these requests, so the API could not cast the `schedule_ids` (or `recipients`) payload. It was fixed by the headers change shipped in @knocklabs/node 6.5. Upgrade from 6.1 to 6.5 or later; the reporter confirmed the error disappears after updating.
Source: https://github.com/knocklabs/knock-node/issues/52
## How to use this
Take the question above and check if it matches what you're seeing. If it does, work through the verified fix step by step. Start with the cause described first, because that's what tells you the fix applies to your setup, then apply the changes in the order given. Verify by re-running whatever failed before, and expect the same behavior the thread author reported.