Update welcome-app-gateway.yml

Author: gitanjali1993

support/azure/application-gateway/welcome-app-gateway.yml

@@ -1 +1,26 @@
-TBD
+### YamlMime:Landing
+
+title: Azure Application Gateway troubleshooting documentation
+summary: Welcome to Azure Application Gateway troubleshooting. These articles explain how to determine, diagnose, and fix various issues that you might encounter when you use Azure Application Gateway. In the navigation pane on the left, browse through the article list or use the search box to find issues and solutions.
+
+metadata:
+  title: Troubleshoot common issues with Azure Application Gateway
+  description: Documentation for troubleshooting common issues with Azure Application Gateway. # Required; article description that is displayed in search results. < 160 chars.
+  services: azure
+  ms.service: azure-application-gateway
+  ms.topic: landing-page # Required
+  author: gitanjali1993  #Required; your GitHub user alias, with correct capitalization.
+  ms.author: giverm #Required; microsoft alias of author; optional team alias.
+  ms.date: 01/27/2026
+
+# linkListType: architecture | concept | deploy | download | get-started | how-to-guide | learn | overview | quickstart | reference | tutorial | video | whats-new
+
+landingContent:
+
+ # Card
+  - title: Azure Application Gateway
+    linkLists:
+      - linkListType: how-to-guide
+        links:
+          - text: Azure API is returning blank response
+            url: error-codes/applicationgatewayskunotspecified.md