diff --git a/examples/socketmode_handler/socketmode_handler.go b/examples/socketmode_handler/socketmode_handler.go
index 9991e8c3c..221c3ea23 100644
--- a/examples/socketmode_handler/socketmode_handler.go
+++ b/examples/socketmode_handler/socketmode_handler.go
@@ -15,7 +15,7 @@ import (
 func main() {
 	appToken := os.Getenv("SLACK_APP_TOKEN")
 	if appToken == "" {
-
+		panic("SLACK_APP_TOKEN must be set.\n")
 	}
 
 	if !strings.HasPrefix(appToken, "xapp-") {