Update setup.py.server.in

python/setup.py.server.in

@@ -32,7 +32,7 @@ max_version, mid_version, min_version = util.python_version()
 util.gen_pipeline_code("paddle_serving_server")
 
 REQUIRED_PACKAGES = [
-    'six >= 1.10.0', 'protobuf >= 3.11.0', 'grpcio <= 1.33.2', 'grpcio-tools >= 1.28.1',
+    'six >= 1.10.0', 'protobuf >= 3.11.0', 'grpcio <= 1.33.2', 'grpcio-tools <= 1.33.2',
     'flask >= 1.1.1,<2.0.0', 'click==7.1.2', 'itsdangerous==1.1.0', 'Jinja2==2.11.3',
     'MarkupSafe==1.1.1', 'Werkzeug==1.0.1', 'func_timeout', 'pyyaml', 'pytest'
 ]