diff --git a/src/Rfc1035StubDnsResolver.php b/src/Rfc1035StubDnsResolver.php
index 1d4d9ff..c14c171 100644
--- a/src/Rfc1035StubDnsResolver.php
+++ b/src/Rfc1035StubDnsResolver.php
@@ -559,7 +559,7 @@ final class Rfc1035StubDnsResolver implements DnsResolver
         return $nameservers;
     }
 
-    private function shouldRetry(int $code): bool
+    private function shouldRetry(int|string $code): bool
     {
         return \in_array($code, [
             MessageResponseCodes::SERVER_FAILURE,