diff --git a/proxy/src/main/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivity.java b/proxy/src/main/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivity.java
index abc23a53a3e..3db3f715743 100644
--- a/proxy/src/main/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivity.java
+++ b/proxy/src/main/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivity.java
@@ -146,7 +146,7 @@ public CompletableFuture<NotifyClientTerminationResponse> notifyClientTerminatio
 
         try {
             String clientId = ctx.getClientID();
-            LanguageCode languageCode = LanguageCode.valueOf(ctx.getLanguage());
+            LanguageCode languageCode = parseLanguage(ctx);
             Settings clientSettings = grpcClientSettingsManager.removeAndGetClientSettings(ctx);
             if (clientSettings == null) {
                 future.complete(NotifyClientTerminationResponse.newBuilder()
@@ -415,7 +415,7 @@ protected TelemetryCommand processClientSettings(ProxyContext ctx, TelemetryComm
 
     protected GrpcClientChannel registerProducer(ProxyContext ctx, String topicName) {
         String clientId = ctx.getClientID();
-        LanguageCode languageCode = LanguageCode.valueOf(ctx.getLanguage());
+        LanguageCode languageCode = parseLanguage(ctx);
 
         GrpcClientChannel channel = this.grpcChannelManager.createChannel(ctx, clientId);
         // use topic name as producer group
@@ -431,7 +431,7 @@ protected GrpcClientChannel registerProducer(ProxyContext ctx, String topicName)
     protected GrpcClientChannel registerConsumer(ProxyContext ctx, String consumerGroup, ClientType clientType,
         List<SubscriptionEntry> subscriptionEntryList, boolean updateSubscription) {
         String clientId = ctx.getClientID();
-        LanguageCode languageCode = LanguageCode.valueOf(ctx.getLanguage());
+        LanguageCode languageCode = parseLanguage(ctx);
 
         GrpcClientChannel channel = this.grpcChannelManager.createChannel(ctx, clientId);
         ClientChannelInfo clientChannelInfo = new ClientChannelInfo(channel, clientId, languageCode, parseClientVersion(ctx.getClientVersion()));
@@ -461,6 +461,18 @@ private int parseClientVersion(String clientVersionStr) {
         return clientVersion;
     }
 
+    private LanguageCode parseLanguage(ProxyContext ctx) {
+        String language = ctx.getLanguage();
+        if (StringUtils.isBlank(language)) {
+            throw new GrpcProxyException(Code.BAD_REQUEST, "language cannot be empty");
+        }
+        try {
+            return LanguageCode.valueOf(language);
+        } catch (IllegalArgumentException e) {
+            throw new GrpcProxyException(Code.BAD_REQUEST, "unsupported language: " + language, e);
+        }
+    }
+
     protected void reportThreadStackTrace(ProxyContext ctx, Status status, ThreadStackTrace request) {
         String nonce = request.getNonce();
         String threadStack = request.getThreadStackTrace();
diff --git a/proxy/src/test/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivityTest.java b/proxy/src/test/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivityTest.java
index e215c6efaba..11c7bc4891e 100644
--- a/proxy/src/test/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivityTest.java
+++ b/proxy/src/test/java/org/apache/rocketmq/proxy/grpc/v2/client/ClientActivityTest.java
@@ -325,6 +325,44 @@ public void testErrorProducerConfig() throws Throwable {
         }
     }
 
+    @Test
+    public void testInvalidLanguageIsReportedAsInvalidArgument() throws Throwable {
+        ProxyContext context = createContext().setLanguage("UNKNOWN_LANGUAGE");
+        try {
+            this.sendClientTelemetry(
+                context,
+                Settings.newBuilder()
+                    .setClientType(ClientType.PRODUCER)
+                    .setPublishing(Publishing.newBuilder()
+                        .addTopics(Resource.newBuilder().setName(TOPIC).build())
+                        .build())
+                    .build()).get();
+            fail();
+        } catch (ExecutionException e) {
+            StatusRuntimeException exception = (StatusRuntimeException) e.getCause();
+            assertEquals(Status.Code.INVALID_ARGUMENT, exception.getStatus().getCode());
+        }
+    }
+
+    @Test
+    public void testBlankLanguageIsReportedAsInvalidArgument() throws Throwable {
+        ProxyContext context = createContext().setLanguage("");
+        try {
+            this.sendClientTelemetry(
+                context,
+                Settings.newBuilder()
+                    .setClientType(ClientType.PRODUCER)
+                    .setPublishing(Publishing.newBuilder()
+                        .addTopics(Resource.newBuilder().setName(TOPIC).build())
+                        .build())
+                    .build()).get();
+            fail();
+        } catch (ExecutionException e) {
+            StatusRuntimeException exception = (StatusRuntimeException) e.getCause();
+            assertEquals(Status.Code.INVALID_ARGUMENT, exception.getStatus().getCode());
+        }
+    }
+
     @Test
     public void testEmptySettings() throws Throwable {
         ProxyContext context = createContext();