diff --git a/src/addons/outlook/src/success/success.html b/src/addons/outlook/src/success/success.html
index 2ac114b3..d1603e88 100644
--- a/src/addons/outlook/src/success/success.html
+++ b/src/addons/outlook/src/success/success.html
@@ -40,5 +40,8 @@
                         </svg>
                     </span>
         </div>
+        <p id="close-msg" style="display: none; text-align: center; font-size: 13px; color: #666; margin-top: 16px;">
+            Si cette fenêtre ne se ferme pas toute seule, veuillez la fermer manuellement.
+        </p>
     </body>
 </html>
diff --git a/src/addons/outlook/src/success/success.js b/src/addons/outlook/src/success/success.js
index 0c2da273..ccd0082d 100644
--- a/src/addons/outlook/src/success/success.js
+++ b/src/addons/outlook/src/success/success.js
@@ -11,10 +11,18 @@ if (!transitToken) {
   window.close();
 } else {
   exchangeSession(transitToken)
+    .then(() => {
+      document.querySelector(".spinner-container").style.display = "none";
+      document.querySelector("#close-msg").style.display = "block";
+    })
     .catch((e) => {
       console.error(`Error occured: ${e}`);
     })
     .finally(() => {
+      // NOTE: doesn't work with the desktop client — the browser considers
+      // this window wasn't opened by this script (it was opened externally),
+      // so it blocks window.close() for security reasons. The "#close-msg"
+      // shown above is the fallback for that case.g
       window.close();
     });
 }