Video upload getting 400 error

I’m trying to implement the Direct Creator Upload flow as described here:

I’m using flutter/android.

This is the process:

  1. I’m calling the first POST request from postman, and getting a tokenized url in the form of<id>?tusv2=true

  2. Then I’m making a HEAD request to the url, and I’m getting status 200, and the offset 0.

  3. Then I’m making a PATCH request to the same url with headers:

 "Tus-Resumable": "1.0.0"
"Upload-Offset", "0"
"Content-Type", "application/offset+octet-stream"

And getting error 400.