diff --git a/src/pocketmine/Server.php b/src/pocketmine/Server.php
index 332c8b262..382d62da9 100644
--- a/src/pocketmine/Server.php
+++ b/src/pocketmine/Server.php
@@ -890,7 +890,7 @@ class Server{
 			return false;
 		}
 
-		if($generator !== false and class_exists($generator) and is_subclass_of($generator, "pocketmine\\level\\generator\\Generator")){
+		if($generator !== null and class_exists($generator) and is_subclass_of($generator, "pocketmine\\level\\generator\\Generator")){
 			$generator = new $generator($options);
 		}else{
 			if(strtoupper($this->getLevelType()) == "FLAT"){
@@ -1842,4 +1842,4 @@ class Server{
 		return false;
 	}
 
-}
\ No newline at end of file
+}