Cannot use UrlFetchApp in Execution API script

[Tom Doan]

I have two scripts:

A. deployed as Web App

B. deployed as Execution API

In script B, I'm trying to use UrlFetchApp.fetch() to request something from script A, but I get this error in the response:

{
  "done": true,
  "response": {
    "@type": "type.googleapis.com/google.apps.script.v1.ExecutionResponse",
    "result": {
      "error": "\"You do not have permission to call UrlFetchApp.fetch. Required permissions: https://www.googleapis.com/auth/script.external_request\""
    }
  }
}

Script B appscript.json:

{

  "exceptionLogging": "STACKDRIVER",

  "runtimeVersion": "V8",

  "executionApi": {

    "access": "ANYONE"

  },

  "oauthScopes": [

    "https://www.googleapis.com/auth/script.external_request"

  ],

  "urlFetchWhitelist": [

    "https://script.google.com/"

  ]

}

Are Execution API scripts not allowed to use UrlFetchApp.fetch() or am I doing something wrong?

[Andrew Apell]

This looks like an OAuth issue. You might need to have your project verified.