The referenced project is a non self-contained executable. A non self-contained executable cannot be referenced by a self-contained executable

I'm having an issue regarding trying to compile my .netcore3.1 after updated the SDK to .NET 6.0 preview while debugging through Visual Studio. My CSProject is bellow :

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
    <UserSecretsId>f5884bc9-1eeb-1458-bba9-832ed8f4cd4e</UserSecretsId> 
    
</Project>

my dotnet sdk installed :

.NET SDK (reflecting any global.json):
 Version:   6.0.100-preview.5.21302.13
 Commit:    d6380bcae7

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\6.0.100-preview.5.21302.13\

Host (useful for support):
  Version: 6.0.0-preview.5.21301.5
  Commit:  ec3e0b276b

.NET SDKs installed:
  1.1.14 [C:\Program Files\dotnet\sdk]
  2.1.519 [C:\Program Files\dotnet\sdk]
  2.2.104 [C:\Program Files\dotnet\sdk]
  3.0.103 [C:\Program Files\dotnet\sdk]
  3.1.300 [C:\Program Files\dotnet\sdk]
  5.0.301 [C:\Program Files\dotnet\sdk]
  6.0.100-preview.5.21302.13 [C:\Program Files\dotnet\sdk]

error messages :

The referenced project is a non self-contained executable. A non self-contained executable cannot be referenced by a self-contained executable.