diff --git a/docs/i_u_m/i_u_m_migration.en.md b/docs/i_u_m/i_u_m_migration.en.md
index 9f8c8ae1e..793fbf12a 100644
--- a/docs/i_u_m/i_u_m_migration.en.md
+++ b/docs/i_u_m/i_u_m_migration.en.md
@@ -44,4 +44,4 @@ docker compose pull
 docker compose up -d
 ```
 
-**9\.** Finally, change your DNS settings to point to the target server.
+**9\.** Finally, change your DNS settings to point to the target server. Also check the `SNAT_TO_SOURCE` variable in your `mailcow.conf` file if you have changed your public IP address, otherwise SOGo may not work.