diff --git a/README.md b/README.md
index fec1b82..aa28a04 100644
--- a/README.md
+++ b/README.md
@@ -40,6 +40,16 @@ Kanboard is a simple visual task board web application.
 
 ## Additional information
 
+### How to connect as external (non-SSOwat) users
+
+You have to edit this file `/var/www/kanboard/config.php`, find the line `define('REVERSE_PROXY_AUTH', true);` and change it from `true` to `false`.
+**Warning** this disables the possibility to connect with SSOwat users. You will *only* be able to connect with Kanboard users created inside of Kanboard.
+Then you can connect.
+
+**NB**: if you don't make that change, you will get the following error message "Access Forbidden".
+
+This is due to a Kanboard limitation.
+
 ## Links
 
  * Report a bug: https://github.com/YunoHost-Apps/kanboard_ynh/issues