question

Making this conversation private since you've shared your API keys and user credentials via the graphic (and we wouldn't want someone to hack your account with this information).

I see you're trying to hit the Production API Endpoint URI: https://platform.ringcentral.com/restapi/oauth/token are your keys being used for that environment or are they for the Sandbox API Endpoint URI: https://platform.devtest.ringcentral.com/restapi/oauth/token ?

Are the user credentials being used associated with the appropriate environment?

Before testing the service, following things to be checked:

correct client I'd and secret, username should be phone number and extention number should be correct and allowed permission and correct url based on environment like sandbox/ production

Hello all,
i am trying to use rest api for devtest password based authorization. but i am get error "Unsupported grant type" with error code "OAU-250" even i have used the correct Content type and my app has password flow selected

Hi @kakar thanks for the screenshots, what I don't see in there is the base 64 encoding of your Client ID and Secret before you send the postman auth request. Add this code to do the same inside of "Pre-request Script". Note that you need to have those as environment variables or you can just hard code those values inside of this script.

Give it a shot and let me know the result.

// Populate the Postman environment with:
// RC_SERVER_HOSTNAME, RC_APP_KEY, RC_APP_SECRET,
// RC_USERNAME, RC_EXTENSION, RC_PASSWORD
var appKey = environment["RC_APP_KEY"];
var appSecret = environment["RC_APP_SECRET"];
var apiKey = encodeBasicAuthHeader(appKey, appSecret);

postman.setEnvironmentVariable("basic_auth_header", "Basic ".concat(apiKey));

function encodeBasicAuthHeader(appKey, appSecret) {
    var apiKey = appKey + ':' + appSecret;
    return btoa(apiKey);
}