diff --git a/dnsapi.md b/dnsapi.md
index ffceebe..416b7d5 100644
--- a/dnsapi.md
+++ b/dnsapi.md
@@ -2195,8 +2195,8 @@ To issue a cert:
 ## 107. Use dyndnsfree.de API
 
 ```sh
-export df_user="XXX"
-export df_password="XXX"
+export DF_user="XXX"
+export DF_password="XXX"
 ```
 
 To issue a cert: