diff --git a/server/errors.json b/server/errors.json
index 3ea6351468..92f664ba74 100644
--- a/server/errors.json
+++ b/server/errors.json
@@ -1398,5 +1398,15 @@
     "help": "",
     "url": "",
     "deprecates": ""
+  },
+  {
+    "constant": "JSMirrorInvalidStreamName",
+    "code": 400,
+    "error_code": 10142,
+    "description": "source stream name is invalid",
+    "comment": "",
+    "help": "",
+    "url": "",
+    "deprecates": ""
   }
 ]
\ No newline at end of file
diff --git a/server/jetstream_errors_generated.go b/server/jetstream_errors_generated.go
index b5e758313a..75ece6ea43 100644
--- a/server/jetstream_errors_generated.go
+++ b/server/jetstream_errors_generated.go
@@ -224,6 +224,9 @@ const (
 	// JSMirrorConsumerSetupFailedErrF generic mirror consumer setup failure string ({err})
 	JSMirrorConsumerSetupFailedErrF ErrorIdentifier = 10029
 
+	// JSMirrorInvalidStreamName source stream name is invalid
+	JSMirrorInvalidStreamName ErrorIdentifier = 10142
+
 	// JSMirrorMaxMessageSizeTooBigErr stream mirror must have max message size >= source
 	JSMirrorMaxMessageSizeTooBigErr ErrorIdentifier = 10030
 
@@ -501,6 +504,7 @@ var (
 		JSMaximumStreamsLimitErr:                   {Code: 400, ErrCode: 10027, Description: "maximum number of streams reached"},
 		JSMemoryResourcesExceededErr:               {Code: 500, ErrCode: 10028, Description: "insufficient memory resources available"},
 		JSMirrorConsumerSetupFailedErrF:            {Code: 500, ErrCode: 10029, Description: "{err}"},
+		JSMirrorInvalidStreamName:                  {Code: 400, ErrCode: 10142, Description: "source stream name is invalid"},
 		JSMirrorMaxMessageSizeTooBigErr:            {Code: 400, ErrCode: 10030, Description: "stream mirror must have max message size >= source"},
 		JSMirrorWithSourcesErr:                     {Code: 400, ErrCode: 10031, Description: "stream mirrors can not also contain other sources"},
 		JSMirrorWithStartSeqAndTimeErr:             {Code: 400, ErrCode: 10032, Description: "stream mirrors can not have both start seq and start time configured"},
@@ -1389,6 +1393,16 @@ func NewJSMirrorConsumerSetupFailedError(err error, opts ...ErrorOption) *ApiErr
 	}
 }
 
+// NewJSMirrorInvalidStreamNameError creates a new JSMirrorInvalidStreamName error: "source stream name is invalid"
+func NewJSMirrorInvalidStreamNameError(opts ...ErrorOption) *ApiError {
+	eopts := parseOpts(opts)
+	if ae, ok := eopts.err.(*ApiError); ok {
+		return ae
+	}
+
+	return ApiErrors[JSMirrorInvalidStreamName]
+}
+
 // NewJSMirrorMaxMessageSizeTooBigError creates a new JSMirrorMaxMessageSizeTooBigErr error: "stream mirror must have max message size >= source"
 func NewJSMirrorMaxMessageSizeTooBigError(opts ...ErrorOption) *ApiError {
 	eopts := parseOpts(opts)
diff --git a/server/jetstream_super_cluster_test.go b/server/jetstream_super_cluster_test.go
index 8abbe17c40..779de18b88 100644
--- a/server/jetstream_super_cluster_test.go
+++ b/server/jetstream_super_cluster_test.go
@@ -550,7 +550,7 @@ func TestJetStreamSuperClusterConnectionCount(t *testing.T) {
 		require_NoError(t, err)
 		_, err = js.AddStream(&nats.StreamConfig{
 			Name:     "src",
-			Sources:  []*nats.StreamSource{{Name: "foo.1"}, {Name: "foo.2"}},
+			Sources:  []*nats.StreamSource{{Name: "foo1"}, {Name: "foo2"}},
 			Replicas: 3})
 		require_NoError(t, err)
 	}()
@@ -561,7 +561,7 @@ func TestJetStreamSuperClusterConnectionCount(t *testing.T) {
 		require_NoError(t, err)
 		_, err = js.AddStream(&nats.StreamConfig{
 			Name:     "mir",
-			Mirror:   &nats.StreamSource{Name: "foo.2"},
+			Mirror:   &nats.StreamSource{Name: "foo2"},
 			Replicas: 3})
 		require_NoError(t, err)
 	}()
diff --git a/server/stream.go b/server/stream.go
index 976ee60013..6bced4495c 100644
--- a/server/stream.go
+++ b/server/stream.go
@@ -1164,6 +1164,9 @@ func (s *Server) checkStreamCfg(config *StreamConfig, acc *Account) (StreamConfi
 		// Do not perform checks if External is provided, as it could lead to
 		// checking against itself (if sourced stream name is the same on different JetStream)
 		if cfg.Mirror.External == nil {
+			if !isValidName(cfg.Mirror.Name) {
+				return StreamConfig{}, NewJSMirrorInvalidStreamNameError()
+			}
 			// We do not require other stream to exist anymore, but if we can see it check payloads.
 			exists, maxMsgSize, subs := hasStream(cfg.Mirror.Name)
 			if len(subs) > 0 {