Hi Narinder Paul,
Thanks for reaching out to Microsoft!
Could you please check the sensitivity labels in the Purview Portal to ensure they have valid descriptions and have been applied successfully?
Additionally, try the following steps using the Postman Application. Assign the "InformationProtectionPolicy.Read.All" application permission and run the Graph API call below to check if still getting the same error?
GET https://graph.microsoft.com/beta/users/{UserPrincipalName}/security/informationProtection/sensitivityLabels
Note: APIs under the /beta version in Microsoft Graph are subject to change. Use of these APIs in production applications is not supported. To determine whether an API is available in v1.0, use the Version selector.
Hope this helps.
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