Fix link

Author: johndowns

articles/reliability/reliability-app-service.md

@@ -67,7 +67,7 @@ Instance spreading with a zone-redundant deployment is determined using the foll
 
     - The instances distribute evenly if you specify a capacity (number of instances) greater than *maximumNumberOfZones* and the number of instances is divisible by *maximumNumberOfZones*.
     - Any remaining instances are distributed across the remaining zones.
-    - When the App Service platform allocates instances for a zone-redundant App Service plan, it uses best-effort zone balancing that the underlying Azure virtual machine scale sets provide. An App Service plan is balanced if each zone has the same number of VMs or differs by plus one VM or minus one VM from all other zones. For more information, see Zone balancing.
+    - When the App Service platform allocates instances for a zone-redundant App Service plan, it uses best-effort zone balancing that the underlying Azure virtual machine scale sets provide. An App Service plan is balanced if each zone has the same number of VMs or differs by plus one VM or minus one VM from all other zones. For more information, see [Zone balancing](/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-use-availability-zones#zone-balancing).
 
 - **Physical zone placement** You can view the [physical availability zone](availability-zones-overview.md#physical-and-logical-availability-zones) used for each of your App Service plan instances. Use the [REST API](/rest/api/appservice/web-apps/get-instance-info), which returns the `physicalZone` value for each instance.