Creating a Milestone for a Github Project via REST - rest

Question

I would like to use the REST API of Github to manage the milestones and labels of some of my repositories, but I constantly fail to create new milestones or labels via REST. What do I miss?
I enable 2FA for my account and also create a personal access token, as it is described in Other Authentication Methods
For example I try to create a new milestone with this cURL command:
curl -X POST -v \
-H "Authorization: token MyPersonalAccessToken" \
-H "Content-Type: application/json" \
-H "Accept: application/vnd.github.v3+json" \
-d '{"title": "1", "state": "open", "description": "Milestone", "due_on": "2025-10-09T23:39:01Z"}' \
https://api.github.com/repos/obfischer/boxsack/milestones
I tried various other variants but all seems to be wrong. At least I always get only a 404 Not Found. According to the Github documentation this could also mean that my authentication failed, as Github returns a 404 Not Found response code to protect user data instead of returning a 401 Unauthorized.
But I am pretty sure that the authentication via the Person Access Token is working as I can see a user specific rate-limit headers in the response:
X-RateLimit-Limit: 5000
X-RateLimit-Remaining: 4999
Does someone have a clue why I can't create a milestone via REST?

Answer 1

Maybe your personal access token doesn't have the repo scope. I've just tested to send the request with a token without that scope & it also returns 404 :
< HTTP/1.1 404 Not Found
< Date: Sat, 26 Oct 2019 11:07:31 GMT
< Content-Type: application/json; charset=utf-8
< Content-Length: 125
< Server: GitHub.com
< Status: 404 Not Found
< X-RateLimit-Limit: 5000
< X-RateLimit-Remaining: 4989
< X-RateLimit-Reset: 1572091544
< X-OAuth-Scopes: [Here there should be repo] <================
< X-Accepted-OAuth-Scopes:
< X-GitHub-Media-Type: github.v3; format=json
< Access-Control-Expose-Headers: ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type
< Access-Control-Allow-Origin: *
< Strict-Transport-Security: max-age=31536000; includeSubdomains; preload
< X-Frame-Options: deny
< X-Content-Type-Options: nosniff
< X-XSS-Protection: 1; mode=block
< Referrer-Policy: origin-when-cross-origin, strict-origin-when-cross-origin
< Content-Security-Policy: default-src 'none'
< X-GitHub-Request-Id: 87B2:23EED:36F2B7F:42647AE:5DB428F3
<
{
"message": "Not Found",
"documentation_url": "https://developer.github.com/v3/issues/milestones/#create-a-milestone"
}