diff --git a/addons/mail/static/src/models/attachment_viewer_viewable.js b/addons/mail/static/src/models/attachment_viewer_viewable.js
index eeb5509cb06..dcf85674d42 100644
--- a/addons/mail/static/src/models/attachment_viewer_viewable.js
+++ b/addons/mail/static/src/models/attachment_viewer_viewable.js
@@ -15,12 +15,6 @@ registerModel({
         download() {
             return this.attachmentOwner.download();
         },
-        /**
-         * @private
-         */
-        _computeAccessToken() {
-            return this.attachmentOwner.accessToken;
-        },
         /**
          * @private
          */
@@ -97,9 +91,6 @@ registerModel({
             identifying: true,
             inverse: 'attachmentViewerViewable',
         }),
-        accessToken: attr({
-            compute: "_computeAccessToken",
-        }),
         defaultSource: attr({
             compute: "_computeDefaultSource",
         }),
diff --git a/addons/mail/static/tests/helpers/webclient_setup.js b/addons/mail/static/tests/helpers/webclient_setup.js
index 0fc6a3f415a..231ccc7b6b9 100644
--- a/addons/mail/static/tests/helpers/webclient_setup.js
+++ b/addons/mail/static/tests/helpers/webclient_setup.js
@@ -62,10 +62,11 @@ function setupMessagingServiceRegistries({
     const serviceRegistry = registry.category('services');
 
     patchWithCleanup(messagingService, {
-        async _startModelManager() {
+        async _startModelManager(modelManager, messagingValues) {
+            modelManager.isDebug = true;
             const _super = this._super.bind(this);
             await messagingBeforeCreationDeferred;
-            return _super(...arguments);
+            return _super(modelManager, messagingValues);
         },
     });