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Unauthorized for this grant type - OAU-250
Tags: authentication
Apr 28, 2019 at 11:30pm   •   3 replies  •  0 likes

Hello Team,

We want to implement calling functionality in our Application for that we have decided to use RingCentral for that first we need to check it in the demo application. We are using PHP Package.

Here are the details of our Demo Application.

Application Name: SAMI-Aid

Client ID: gyNTMqexxxxxxx
Client Secret:

Phone number: 1608729xxxx

Application Type: Private

Platform Type: Server/Web

Permissions Needed : CallControl , RingOut, SMS, VoIP calling, ReadCallLog, SubscriptionWebhook

Now when I am trying to generate an access token using curl request I got an error like below

curl Request :

curl -X POST "" panel, It's working fine. Please find Attachment

3 Answers
answered on Jun 17, 2019 at 10:47pm  

If you're using an OAuth 2.0 request using the OAuth 2.0 password grant (grant_type=password), then your application you created should in the RingCentral Developer Portal should be Password flow .

Please note, application created with different platform type will have different grant_type.

For example, application created for platform type = browser based will have grant_type=Authorization Code | Implicit | Refresh Access Token where as application for platform type = Desktop/Windows will have grant_type= Authorization Code | Password flow |Refresh Access Token

So in order to use (grant_type=password) you need to have application created with platform type that support Password flow

Here is wonderful way it has answered with animated Gif image that will easily help you to understand the proccess:

answered on Apr 29, 2019 at 10:27am  
If you move on with the current app, see this quick start for a demo

Otherwise, if you want to use the password flow authentication, create a new app and select the Server-only (No UI) for the Platform Type. See this demo

answered on Apr 29, 2019 at 7:13am  
For security reasons you have to use 3-legged OAuth flow with authorization_code grant type in web applications. See


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