Error creating "shadow" customer with two-legged authentication

Hi, what I am currently trying to do is create a new shadow customer in the Particle system. So far I created a product in the dashboard as well as an oAuth client that has the create customer scope. When I tried to make a request to the following endpoint:

I get the following error:

   "code" : 400,
   "error" : {
      "code" : 503,
      "message" : "No valid scopes",
      "headers" : {
         "Pragma" : "no-cache",
         "Cache-Control" : "no-store"
      "error_description" : "server_error",
      "stack" : "Error: No valid scopes\n    at OAuth2ServerModel.saveAccessToken (/opt/particle-base/api_service/releases/b8eebe48646483604720ac88fb71e61d7e7e5655/lib/OAuth2ServerModel.js:117:19)\n    at Grant.saveAccessToken (/opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/grant.js:421:14)\n    at run (/opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/runner.js:15:14)\n    at /opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/runner.js:17:7\n    at /opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/grant.js:396:3\n    at OAuth2ServerModel.generateExpiresTime (/opt/particle-base/api_service/releases/b8eebe48646483604720ac88fb71e61d7e7e5655/lib/OAuth2ServerModel.js:232:3)\n    at Grant.generateExpiresTime (/opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/grant.js:388:13)\n    at run (/opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/runner.js:15:14)\n    at /opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/runner.js:17:7\n    at /opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/grant.js:376:5\n    at InternalFieldObject.ondone (/opt/particle-base/api_service/shared/vendor/node_modules/oauth2-server/lib/token.js:55:5)",
      "error" : "server_error",
      "name" : "OAuth2Error"
   "ok" : false

I am including the no_password=true, and the user’s email in the body of the POST request and setting the Content-Type header to “application/x-www-form-urlencoded”. To make the situation even more complicated, when I try to make the request again I get the following error:


which leads me to believe the user was actually created partially during the first request. This customer is not showing up under my product in the Particle dashboard though. If anyone has any tips for how to resolve this and can point out what was wrong with the original request that would be very helpful. Thanks in advance.

Seems to be a duplicate of this post: