From b4ff9286ce911ec47351a29f33e005cc81175115 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=88=E5=9B=BD=E4=BC=9F?= <366193849@qq.com>
Date: Mon, 30 Aug 2021 12:01:59 +0800
Subject: [PATCH] =?UTF-8?q?null=E5=88=A4=E6=96=AD?=
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---
 FastGithub.DomainResolve/DomainResolver.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/FastGithub.DomainResolve/DomainResolver.cs b/FastGithub.DomainResolve/DomainResolver.cs
index 0be2b36..be9f64a 100644
--- a/FastGithub.DomainResolve/DomainResolver.cs
+++ b/FastGithub.DomainResolve/DomainResolver.cs
@@ -105,7 +105,7 @@ namespace FastGithub.DomainResolve
         /// <returns></returns>
         private async Task<IPAddress?> ResolveCoreAsync(DnsEndPoint domain, CancellationToken cancellationToken)
         {
-            if (this.domainResolveCache.TryGetValue<IPAddress>(domain, out var address))
+            if (this.domainResolveCache.TryGetValue<IPAddress>(domain, out var address) && address != null)
             {
                 return address;
             }
@@ -124,7 +124,7 @@ namespace FastGithub.DomainResolve
 
             if (address == null)
             {
-                return default;
+                return null;
             }
 
             // 往往是被污染的dns