diff --git a/common/scala/src/main/scala/org/apache/openwhisk/http/ErrorResponse.scala b/common/scala/src/main/scala/org/apache/openwhisk/http/ErrorResponse.scala
index 5424dd309f7..96654466d03 100644
--- a/common/scala/src/main/scala/org/apache/openwhisk/http/ErrorResponse.scala
+++ b/common/scala/src/main/scala/org/apache/openwhisk/http/ErrorResponse.scala
@@ -72,7 +72,7 @@ object Messages {
 
   /** Standard message for too many concurrent activation requests within a time window. */
   def tooManyConcurrentRequests(count: Int, allowed: Int) =
-    s"Too many concurrent requests in flight (count: $count, allowed: $allowed)."
+    s"Too many concurrent requests in flight (currently running: $count, allowed per controller: $allowed)."
 
   /** System overload message. */
   val systemOverloaded = "System is overloaded, try again later."
diff --git a/tests/src/test/scala/limits/ThrottleTests.scala b/tests/src/test/scala/limits/ThrottleTests.scala
index 7b9e00fad60..9f76ff4f0c3 100644
--- a/tests/src/test/scala/limits/ThrottleTests.scala
+++ b/tests/src/test/scala/limits/ThrottleTests.scala
@@ -467,7 +467,7 @@ class NamespaceSpecificThrottleTests
     }
 
     wsk.action.invoke(actionName, expectedExitCode = TooManyRequests.intValue).stderr should {
-      include(prefix(tooManyConcurrentRequests(0, 0))) and include("allowed: 0")
+      include(prefix(tooManyConcurrentRequests(0, 0))) and include("allowed per controller: 0")
     }
   }