How to use Discovery Service API.

[Go_Ozeki]

I would like to use the Discovery Service API, but even after referring to the following site, it does not work.

As a result, I get a Status 401 Unauthorized response.

https://docs.microsoft.com/en-us/powerapps/developer/data-platform/webapi/discovery-orgsdk-to-webapi

See the images below for Request and Response.

I followed the steps below with reference to MS Learn.

https://docs.microsoft.com/en-us/learn/modules/common-data-service-web-api/

1. Register Dataverse App to Azure AD
2. Modify Manifest in Microsoft CRM Portals
3. Allow API access
4. Generate OAuth 2.0 Access Token by Postman.
5. Execute the WhoAmI function to check the Web API connection to Dataverse, and confirm that the response is Status 200 OK.
6. As a result of executing the Discovery Service API, the status 401 Unauthorized was response.

Please let me know if I am missing some setting or if it is a tenant problem.

Thank you for help.

[v-xiaochen-msft]

Hi @Go_Ozeki ,

Their resources are different.

https://login.microsoftonline.com/common/oauth2/authorize?resource=https://globaldisco.crm.dynamics.com

Get its token and use it.

Best Regards,
Wearsky
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[Go_Ozeki]

Hi @v-xiaochen-msft,

I changed the AuthURL to the one you gave me, got the token, and tried again.
However, the result was the same: 401 Unauthorized.
What are the possible reasons for the 401 Unauthorized?

Thank you.

[v-xiaochen-msft]

Hi @Go_Ozeki ,

Have you given your application enough permissions?

Best Regards,
Wearsky
If my post helps, then please consider Accept it as the solution to help others. Thanks.

[Go_Ozeki]

Hi @v-xiaochen-msft,

I do not have permissions to work with Azure AD.
I will check with my system administrator later or get a developer subscription and try it out.

Thank you for help.

[Go_Ozeki]

Hi @v-xiaochen-msft,

I got a developer subscription and tried the following steps.

1.Granted admin consent for my Environment.

2.Configured the Manifest.

3.Authentication was set to Multitenant.

4.Postman settings.

Auth URL:

https://login.microsoftonline.com/common/oauth2/authorize?resource=https://globaldisco.crm.dynamics.com

However, the result was the same: 401 Unauthorized.
Do I still need to configure something?

Thank you for help.

[v-xiaochen-msft · Accepted solution]

Hi @Go_Ozeki ,

Is the permission of the app now the same as in the image?

Please check if your postman has selected the correct environment and check if your client id and callback are correct.

// Please use Bearer 

Best Regards,
Wearsky
If my post helps, then please consider Accept it as the solution to help others. Thanks.

[ChrisPiasecki]

Hi @Go_Ozeki,

In the 401 response, there should be header called www-authenticate, which should give you a clue as to what resource you need to specify when requesting access.

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[Go_Ozeki]

Hi @v-xiaochen-msft,

I set the Header Prefix to "Bearer" and got the results fine!
All settings except Header Prefix were set as you said.

I am very grateful for all the advice you have given me.

Thank you for help.

[Go_Ozeki]

Hi @ChrisPiasecki,

I checked the www-authenticate and found the following statement, but I couldn't read that setting the Header Prefix to "Bearer" would solve the problem.

Bearer authorization_uri=https://login.microsoftonline.com/common/oauth2/authorize,resource_id=https://globaldisco.crm.dynamics.com/

But your advice was very helpful!

Thank you for help.