diff --git a/packages/cli/src/actions/proxy.ts b/packages/cli/src/actions/proxy.ts
index f3f27ef7..27c80951 100644
--- a/packages/cli/src/actions/proxy.ts
+++ b/packages/cli/src/actions/proxy.ts
@@ -166,6 +166,17 @@ function startServer(client: ClientContract<any, any>, schema: any, options: Opt
         console.log(`You can visit ZenStack Studio at: ${colors.blue('https://studio.zenstack.dev')}`);
     });
 
+    server.on('error', (err: NodeJS.ErrnoException) => {
+        if (err.code === 'EADDRINUSE') {
+            console.error(
+                colors.red(`Port ${options.port} is already in use. Please choose a different port using -p option.`),
+            );
+        } else {
+            throw new CliError(`Failed to start the server: ${err.message}`);
+        }
+        process.exit(1);
+    });
+
     // Graceful shutdown
     process.on('SIGTERM', async () => {
         server.close(() => {
diff --git a/packages/cli/src/index.ts b/packages/cli/src/index.ts
index 82d0e736..e3896606 100644
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -196,7 +196,7 @@ Arguments following -- are passed to the seed script. E.g.: "zen db seed -- --us
         .alias('studio')
         .description('Start the ZenStack proxy server')
         .addOption(schemaOption)
-        .addOption(new Option('-p, --port <port>', 'port to run the proxy server on').default(8008))
+        .addOption(new Option('-p, --port <port>', 'port to run the proxy server on').default(2311))
         .addOption(new Option('-o, --output <path>', 'output directory for `zen generate` command'))
         .addOption(new Option('-d, --databaseUrl <url>', 'database connection URL'))
         .addOption(new Option('-l, --logLevel <level>', 'Query log levels (e.g., query, error)'))