With my cloudflare worker I fail with

Note: Unnecessary use of -X or --request, POST is already inferred.
> content-length: 697
> content-type: application/x-www-form-urlencoded
* We are completely uploaded and fine
* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!
< HTTP/2 400

< server: nginx
< content-length: 28
< strict-transport-security: max-age=63072000
<

* Connection #0 to host api.tinybird.co left intact
Analysis error, invalid data%