diff --git a/addons/im_livechat/static/src/legacy/model/model_manager.js b/addons/im_livechat/static/src/legacy/model/model_manager.js
index da8c23672ae..c54629bee30 100644
--- a/addons/im_livechat/static/src/legacy/model/model_manager.js
+++ b/addons/im_livechat/static/src/legacy/model/model_manager.js
@@ -311,6 +311,9 @@ export class ModelManager {
      * @param {Listener} listener
      */
     removeListener(listener) {
+        if (!listener) {
+            return;
+        }
         this._listeners.delete(listener);
         this._listenersToNotifyInUpdateCycle.delete(listener);
         this._listenersToNotifyAfterUpdateCycle.delete(listener);