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Since the introduction of OAuth 2.0 Authentication in GeneXus Access Manager (GAM), it is possible to authenticate to a broader set of providers. This article explains what to do in GAM backend, to authenticate to Office 365. For more information on how to configure Azure, see Application Registration in Azure Active Directory.

Authentication Type

Add a new OAuth 2.0 authentication type in the Web Backoffice and set the associated basic parameters:

  • Name (you will use this name later in the code to log in)
  • Function (Only Authentication is supported)
  • Enabled (Yes|No)
  • Description: friendly description
  • Small image name
  • Big image name
  • Impersonate

You need to fill in detailed information in the following tabs:

  • General: to identify the OAuth 2.0 application.
  • Authorization: headers associated with the authorization request and response.
  • Token: service URL to handle token information.
  • User Information: service URL to handle user data.

Configuration at GAM backend

Client ID:     client_id        Value: <clientid>
Client Secret: client_secret    Value: <clientsecret>
Redirect URL:  redirect_uri     Value: https://<server>/webapp

Response type TAG:  response_type      Value: code
Scope TAG:          scope              Value:
State TAG:          state
Include ClientID and RedirectURL
Access code TAG: code
Error description TAG: message

Header Cotent type: Content-type      Value: application/x-www-form-urlencoded
Grant type:         grant_type        Value: authorization_code
Include = All
Aditional Parameters:  resource=
Access token TAG: access_token
Token type TAG: token_type
Expires in TAG: expires_in
Error description TAG: message
Validate external token = False

User Information:
Method: Get
Header Content type: Content-type      Value: application/json;charset=utf-8
Do not include anything
Email TAG: mail
External ID TAG: id
Name TAG:  userPrincipalName
First name TAG: givenName
Last name TAG: surname
Language TAG: preferredLanguage
Error description TAG: message

How to use it from the code

Use the LoginOauth20 method from the GAM Repository external object, detailing your OAuth 2.0 configuration name. For example, if you set 'Office365' for the previous configuration:

Event 'Login'
  GAMRepository.LoginOauth20(!"Office365") // Authentication Type Name must match the backend definition


If you want to force a logout from the Identity provider, you will need to invoke the following URL with your desired callback url:<my_callback_URL>


In case of any error, enable the GAM trace to get more information on the error.


AADSTS90002: Tenant organizations not found. This may happen if there are no active subscriptions for the tenant. Check with your subscription administrator.

Check your Azure server-side configuration as it seems the URL configured in GAM is wrong.


AADSTS50011: The reply url specified in the request does not match the reply urls configured for the application: 'GUID'.

Verify your Endpoint URLs are correctly configured and match the location of your GAM application. Go to the Azure portal \ Azure Active Directory application; select your application and check the associated endpoints.



AADSTS70001: Application 'GUID' is disabled.

Check your Azure application is correctly configured.


AADSTS70002: Error validating credentials. AADSTS50012: Invalid client secret is provided

Review the password settings on the Azure application configuration site and update your GAM configuration.


Message: AADSTS50020: We are unable to issue tokens from this api version for a Microsoft account. Please contact the application vendor as they need to use version 2.0 of the protocol to support this.

Review the following Azure registered Application endpoint and the associated configuration within GAM.

  • OAuth 2.0 token endpoint
  • OAuth 2.0 authorization endpoint


OAuth 2.0 authentication is available in GAM since GeneXus 15 Upgrade 11.

See Also

Application Registration in Azure Active Directory
HowTo: Authenticate to Microsoft Entra ID using GAM
GAM - OAuth 2.0 Authentication Type

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