diff --git a/packages/core/src/util/browser.ts b/packages/core/src/util/browser.ts
index b8cc39e52..2fbda3ca1 100644
--- a/packages/core/src/util/browser.ts
+++ b/packages/core/src/util/browser.ts
@@ -1 +1,3 @@
-export const isIe = window.navigator.userAgent.match(/MSIE|Trident/) !== null;
+import { get } from 'lodash-es';
+
+export const isIe = get(window, 'navigator.userAgent', '').match(/MSIE|Trident/) !== null;
diff --git a/packages/core/src/view/Anchor.tsx b/packages/core/src/view/Anchor.tsx
index 4e873d983..53b5e0d2a 100644
--- a/packages/core/src/view/Anchor.tsx
+++ b/packages/core/src/view/Anchor.tsx
@@ -266,7 +266,7 @@ class Anchor extends Component<IProps, IState> {
       const nodeData = targetNode.getData();
       graphModel.eventCenter.emit(EventType.CONNECTION_NOT_ALLOWED, {
         data: nodeData,
-        msg: targetMsg || sourceMsg,
+        msg: targetMsg || sourceMsg || '不允许添加连线',
       });
       return null;
     }