Merge pull request #212299 from flang-msft/fxl---update-ManagedIdentity-doc-to-say-it's-not-supported-on-Cloud-service-caches

fxl---no managed id with cloud cache classic

Author: prmerger-automator[bot]

articles/azure-cache-for-redis/cache-managed-identity.md

@@ -42,7 +42,9 @@ Managed identity can be enabled either when you create a cache instance or after
 
 ### Prerequisites and limitations
 
-Because managed identity for storage is only used with the import/export feature and persistence feature, it's currently only useful when used with the Premium tier of Azure Cache for Redis.
+Managed identity for storage is only used with the import/export feature and persistence feature at present, which limits its use to the Premium tier of Azure Cache for Redis.
+
+Managed identity for storage is not supported on caches that have a dependency on Cloud Services (classic). For more information on how to check on whether your cache is using Cloud Services (classi), see [How do I know if a cache is affected?](cache-faq.yml#how-do-i-know-if-a-cache-is-affected).
 
 ## Create a new cache with managed identity using the portal