diff --git a/.github/workflows/dotnet-release-build.yml b/.github/workflows/dotnet-release-build.yml
index 7eb235d..6b30f83 100644
--- a/.github/workflows/dotnet-release-build.yml
+++ b/.github/workflows/dotnet-release-build.yml
@@ -20,7 +20,7 @@ jobs:
       max-parallel: 21
       fail-fast: false
       matrix:
-        version: [ 2.0, 3.0, 5.0, 6.0, 7.0, 8.0, 9.0 ]
+        version: [ 6.0, 7.0, 8.0, 9.0 ]
         os: [ ubuntu-latest, windows-latest, macos-latest ]
     # config os
     runs-on: ${{ matrix.os }}
diff --git a/test/src/WebSocket.xunit.cs b/test/src/WebSocket.xunit.cs
index 235ccfd..7b234f8 100644
--- a/test/src/WebSocket.xunit.cs
+++ b/test/src/WebSocket.xunit.cs
@@ -111,13 +111,13 @@ public async Task WebSocketConnection()
 
 
         await client.To.Open(new("ws://127.0.0.1:6001/empty"));
-        await Task.Delay(2000);
+        await Task.Delay(6000);
         Assert.False(client.IsOpened);
         Assert.Equal(1 + 2 + 8, index); // open and close: because path;
         index = 0;
 
         await client.To.Open(new("ws://127.0.0.1:112/"));
-        await Task.Delay(200);
+        await Task.Delay(500);
         Assert.False(client.IsOpened);
         Assert.Equal(2 + 4, index); // open and close (NEVER OPENED).
     }