custom_header_blocklisted
One of the custom headers is reserved: the HTTP layer manages it (`host`, `content-type`, `content-length`, `user-agent`), Factuarea sends it as part of the signed contract (`factuarea-*`), or the proxy owns it (`x-forwarded-*`).
| Code | Type | HTTP | Category |
|---|---|---|---|
custom_header_blocklisted | invalid_request_error | 422 | Webhooks |
Cause
One of the custom headers is reserved: the HTTP layer manages it (host, content-type, content-length, user-agent), Factuarea sends it as part of the signed contract (factuarea-*), or the proxy owns it (x-forwarded-*).
What to do
Rename the header — x-my-app-token instead of a reserved one — or drop it if the platform already sends the information.