Not able to fetch data from SharePoint Online List using Postman tool

[Nj-SharePointDeveloper]

Hi,

I followed the process to fetch the data from SP online list using Postman tool:

- Register a new app.

- Generate client id and secret.

- Grant permission

- 

<AppPermissionRequests AllowAppOnlyPolicy="true">
<AppPermissionRequest Scope="http://sharepoint/content/sitecollection/web" Right="FullControl" />
</AppPermissionRequests>

- Trust the app.

Now in Postman

- Generate access token =>https://accounts.accesscontrol.windows.net/MyTokenId/tokens/OAuth/2/

- add following properties in body section

grant_type:client_credentials
client_id:client_id@tenant_id
client_secret:client_secret
resource:00000003-0000-0ff1-ce00-000000000000/YourSharepointOnlineDomainName@tenant_id

- Generate access token. Received successfully.

- Pass this token as "Bearer accessToken".

But now I am facing issue as "{"error":"invalid_request","error_description":"Token type is not allowed."}".

Please guide me, what wrong I am doing here. This SP site is a developer account subscription.

[#2]

Hi @Nj-SharePointDeveloper 

ACS and SharePoint "ClientID" and "Secret" authentication is kind of old.
You need to re-activate it on new tenants using PowerShell as a SharePoint Admin.

It looks like this if you use PnP-Powershell

Connect-PnPOnline https://<yourtenant>-admin.sharepoint.com -Interactive
Set-PnPTenant -DisableCustomAppAuthentication $false

 Then your Postman request will work.

But ACS  is the "old" method...
You should take a look at Azure AD Apps and the "Sites.Selected" permission. 

Best Regards,
Sven

[#3]

Error after running above command  The resource principal named https:// was not found in the tenant named "....". This can happen if the application has not been installed by the administrator of the tenant. etc etc

[#4 · Accepted solution]

Hi @Nj-SharePointDeveloper 

When exactly did you get that error?

• After executing the Powershell command?
  • After the login using "Connect-PnPOnline"?
  • After executing the "Set-PnPTenant" command?
• After acquiring the token? (From https://accounts.accesscontrol.windows.net)
• After executing a SharePoint REST request?

If it occurs during the login using "Connect-PnPOnline" try to execute the following command once before

Register-PnPManagementShellAccess

That registers the PnP Powershell as an app in your tenant.

Best Regards,

Sven