Merge pull request #111621 from abshamsft/patch-39

Update application-gateway-metrics.md

Author: PRMerger16

articles/application-gateway/application-gateway-metrics.md

@@ -98,7 +98,7 @@ For Application Gateway, the following metrics are available:
 
 - **Failed Requests**
 
-  Count of failed requests that Application Gateway has served. The request count can be further filtered to show count per each/specific backend pool-http setting combination.
+  Number of requests that Application Gateway has served with 5xx server error codes. This includes the 5xx codes that are generated from the Application Gateway as well as the 5xx codes that are generated from the backend. The request count can be further filtered to show count per each/specific backend pool-http setting combination.
 
 - **Fixed Billable Capacity Units**
 
@@ -158,7 +158,7 @@ For Application Gateway, the following metrics are available:
 
 - **Failed Requests**
 
-  Count of failed requests that Application Gateway has served. The request count can be further filtered to show count per each/specific backend pool-http setting combination.
+  Number of requests that Application Gateway has served with 5xx server error codes. This includes the 5xx codes that are generated from the Application Gateway as well as the 5xx codes that are generated from the backend. The request count can be further filtered to show count per each/specific backend pool-http setting combination.
 
 - **Response Status**