Update reading time and add troubleshooting guide

docs/4. Product Features/10. Others/06. Collections.md

@@ -1,9 +1,9 @@
 <h3>
  <table>
   <tr>
-    <td><b>5 minutes read</b></td>
+    <td><b>7 minutes read</b></td>
     <td style={{ paddingLeft: '40px' }}><b>Level: Beginner</b></td>
-    <td style={{ paddingLeft: '40px' }}><b>Last Updated: October 2025</b></td>
+    <td style={{ paddingLeft: '40px' }}><b>Last Updated: February 2026</b></td>
   </tr>
 </table>
 </h3>
@@ -265,6 +265,68 @@ Use the Import Contacts feature when you need to add new contacts in bulk into t
 
 
 
+### Contact Not Added to Collection – Troubleshooting Guide
+
+If a contact is not appearing in a collection, please check the following points:
+
+#### 1. Verify if an Add to Collection node exists in the flow.
+
+- Open the flow in the Flow Editor.
+- Check whether there is an Add to Collection node configured.
+- Confirm that the correct collection name is selected.
+- If this node is missing, the contact will never be added to the collection.
+
+**How to fix:**
+
+- Add an Add to Collection node at the appropriate step in the flow.
+- Publish the flow again.
+
+#### 2. Check if the contact actually reached the Add to Collection node.
+
+Sometimes the node exists, but the contact never reaches it due to conditions or flow exits.
+
+**How to verify:**
+
+- Go to the contact’s chat history.
+- Check the flow execution path.
+- Confirm the contact passed through the Add to Collection node.
+
+**Possible reasons:**
+
+- Conditional split redirected the contact elsewhere.
+- Flow exited early.
+
+#### 3. Check if there is a Remove from Collection node immediately after adding.
+
+- If there is a Remove from Collection node using the same collection name right after the Add node, the contact will be removed immediately.
+
+**How to verify:**
+
+
+- Open the flow.
+- Check if a Remove from Collection node exists.
+- Confirm whether it uses the same collection name.
+
+**How to fix:**
+
+- Remove the unnecessary Remove from Collection node, OR
+- Ensure it is only triggered when intended.
+
+#### 4. Confirm the collection name is correct.
+
+- Ensure there are no duplicate collections with similar names.
+
+- Verify the correct collection is selected in the node.
+
+
+
+#### 5. Ensure the flow is published.
+
+- Changes will not work unless the flow is published.
+
+**How to verify:**
+
+- Check if the flow status is Published and not Draft.