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OAU-251 error - Unauthorized for this grant type
Tags: oauth2, authentication, oauth
Jun 7, 2023 at 7:55am   •   1 replies  •  0 likes
Mousa Khalil

I want to generate a JWT for my users, hence, I used the following endpoint alongside the appropriate headers and body, but in order to provide the main JWT for the assertion I was required to created manually for the account. How could I automate it, so that I can create any JWTs using API requests? I tried using password grant_type but it did not work, and throws an OAU-251 error - Unauthorized for this grant type.

Sandbox # +12678284935
Client ID jfEaGJSpQgaMYwr8Q-O1Zg

The following code snippet works fine, but I want to automatically generate the main JWT.

def getAccessToken(username, extension, password, server, client_id, client_secret):
    url = f"{server}/restapi/oauth/token"
    data = {
        "grant_type": "urn:ietf:params:oauth:grant-type:jwt-bearer",
        "username": f"{username}*{extension}",
        "password": password,
    headers = {
        "Content-Type": "application/x-www-form-urlencoded",
        "Authorization": "Basic " + base64.b64encode(f"{client_id}:{client_secret}".encode("utf-8")).decode("utf-8")
    res =, headers=headers, data=data)
    return (res.json())

1 Answer
answered on Jun 7, 2023 at 8:06am  

Please refer to our Dev Guide documentation for instruction how to authenticate with a JWT token. The body data does not take others than just the grant_type and the assertion.


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