diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ddac38b..4143c0b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,7 +11,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: '5.0.0'
+        dotnet-version: '3.1.101'
     - name: Build
       run: dotnet build
   
diff --git a/YYApi.csproj b/YYApi.csproj
index fdeb7a7..c2bdbc2 100644
--- a/YYApi.csproj
+++ b/YYApi.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net5.0</TargetFramework>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
     <OutputType>Library</OutputType>
     <PackOnBuild>true</PackOnBuild>
     <Version>0.2.3</Version>