diff --git a/README.md b/README.md
index b8b7363..d2f5dee 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,7 @@ RDP_PASS="MyWindowsPassword"
 #MULTIMON="true"
 #DEBUG="true"
 ```
+The username and password should be a full user account and password, such as the one created when setting up Windows or a domain user. It cannot be a user/PIN combination as those are not valid for RDP access.
 
 Options:
 - When using a pre-existing non-KVM RDP server, you can use the `RDP_IP` to specify it's location