diff --git a/internal/config/config.go b/internal/config/config.go
index dd8a6cd..188053a 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -80,7 +80,7 @@ func NewDefault() *Config {
 		},
 		Powow: PowowConfig{
 			APIKey:             "powow",
-			InvalidPhoneNumber: "33666666666",
+			InvalidPhoneNumber: "+33666666666",
 		},
 	}
 }
diff --git a/misc/powow.http b/misc/powow.http
index 88d48cc..b7917c1 100644
--- a/misc/powow.http
+++ b/misc/powow.http
@@ -48,6 +48,6 @@ APIKey=powow
 &Command=TransactionalSms.Send
 &ResponseFormat=JSON
 &SmsID={{SmsID}}
-&MobilePhoneNumber=+33666666666
+&MobilePhoneNumber=%2B33666666666
 &TimeToSend=2017-01-01 10:00:00
 &CustomData=a%3A1%3A%7Bs%3A9%3A%22Firstname%22%3Bs%3A8%3A%22am9obg%3D%3D%22%3B%7D
\ No newline at end of file