Merge pull request #9066 from AmandaAZ/Branch-CI5826

AB#5826: Convert blog post to article

Author: Simonx Xu

support/entra/entra-id/toc.yml

@@ -303,6 +303,8 @@
      href: app-integration/404-not-found-error-manage-objects-microsoft-graph.md
    - name: Change enumeration is not supported for requested tenant
      href: users-groups-entra-apis/delta-query-not-supported-for-aad-b2c-tenant.md
+   - name: Graph API request fails to get B2B users using UPN
+     href: users-groups-entra-apis/microsoft-graph-api-query-can-not-get-business-to-business-user.md
    - name: Handling errors in Graph API requests with Invoke-RestMethod
      href: app-integration/graph-api-error-handling-invoke-restmethod.md
    - name: Only one user is returned when running List users API

support/entra/entra-id/users-groups-entra-apis/microsoft-graph-api-query-can-not-get-business-to-business-user.md

@@ -0,0 +1,48 @@
+---
+title: Microsoft Graph API Requests Fail to Get B2B Users Using UPN
+description: Provides a solution to an issue where a Microsoft Graph API request fails to get a Business-to-Business (B2B) user using User Principal Name (UPN).
+ms.service: entra-id
+ms.reviewer: bhvootla, v-weizhu
+ms.custom: sap:Problem with querying or provisioning resources
+ms.date: 06/23/2025
+---
+# Microsoft Graph API requests fail to get B2B users using UPN
+
+This article provides a solution to an error that occurs when you run a Microsoft Graph API request to get a Business-to-Business (B2B) user using User Principal Name (UPN).
+
+## Symptoms
+
+When you execute a Microsoft Graph API request to get a B2B user using UPN, you might encounter an error.
+
+Request example:
+
+`https://graph.microsoft.com/v1.0/users/example_gmail.com#EXT#@example.onmicrosoft.com`
+
+Response exmaple:
+
+```output
+{
+"error": {
+"code": "Request_ResourceNotFound",
+"message": "Resource '<resource-id>' does not exist or one of its queried reference-property objects are not present.",
+"innerError": {
+"request-id": "<request-id>",
+"date": "2019-12-05T23:55:40"
+            }
+        }
+}
+```
+
+## Cause
+
+The issue occurs because the `#` character in the UPN is treated as a special character in the URL. Everything after the `#` is treated as a fragment and isn't sent over the wire.
+
+## Solution
+
+To resolve this issue, you must encode the `#` character in the UPN as `%23`.
+
+Here's the correct request format:
+
+`https://graph.microsoft.com/v1.0/users/example_gmail.com%23EXT%[email protected]`
+
+[!INCLUDE [Azure Help Support](../../../includes/azure-help-support.md)]