diff --git a/index.php b/index.php
index dba1537..a02a6f5 100644
--- a/index.php
+++ b/index.php
@@ -29,7 +29,11 @@ if ($error_reporting) {
 }
 
 if (!file_exists($state_file)) {
-  mkdir($state_file, 0777, true);
+  $dirname = dirname($state_file);
+  if (!is_dir($dirname)) {
+    mkdir($dirname, 0777, true);
+  }
+
   file_put_contents($state_file, json_encode([ "lobbies" => []]));
 }