diff --git a/FastGithub.DomainResolve/DomainResolver.cs b/FastGithub.DomainResolve/DomainResolver.cs
index 3d93b9c..170600b 100644
--- a/FastGithub.DomainResolve/DomainResolver.cs
+++ b/FastGithub.DomainResolve/DomainResolver.cs
@@ -82,7 +82,7 @@ namespace FastGithub.DomainResolve
             var semaphore = this.semaphoreSlims.GetOrAdd(domain, _ => new SemaphoreSlim(1, 1));
             try
             {
-                await semaphore.WaitAsync();
+                await semaphore.WaitAsync(CancellationToken.None);
                 return await this.ResolveCoreAsync(domain, cancellationToken);
             }
             finally
diff --git a/FastGithub.HttpServer/RequestLoggingMilldeware.cs b/FastGithub.HttpServer/RequestLoggingMilldeware.cs
index 2f416c7..5694bad 100644
--- a/FastGithub.HttpServer/RequestLoggingMilldeware.cs
+++ b/FastGithub.HttpServer/RequestLoggingMilldeware.cs
@@ -95,7 +95,7 @@ namespace FastGithub.HttpServer
             while (ex != null)
             {
                 var type = ex.GetType();
-                builder.Append(type.Namespace).Append(".").Append(type.Name).Append(": ").AppendLine(ex.Message);
+                builder.Append(type.Namespace).Append('.').Append(type.Name).Append(": ").AppendLine(ex.Message);
                 ex = ex.InnerException;
             }
             return builder.ToString();