Azure构建管道NuGet恢复错误NETSDK1045

我通过Visual Studio 2019创建了一个Azure CI管道。项目目标框架是.net core 3.1。但是，在NuGet Restore期间会失败。我的计算机上安装了.Net Core 2.2.2017和3.1.101，我的Visual Studio 2019社区版本是16.4。我的环境变量路径到位。

我也尝试过手动创建使用.net core 3.1 LTS堆栈的应用程序服务，但仍然出现相同的错误。

    ##[error]The nuget command failed with exit code(1) and error(C:\Program Files\dotnet\sdk\2.2.110\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(137,5):

    error NETSDK1045: The current .NET SDK does not support targeting .NET Core 3.1.  Either target .NET Core 2.2 or lower, or use a version of the .NET SDK that supports .NET Core 3.1. 

这是Visual Studio生成的YAML文件

pool:
  name: Hosted VS2017
  demands:
  - msbuild
  - visualstudio
  - vstest

steps:
- task: NuGetToolInstaller@1
  displayName: 'Use NuGet 5.0.0'
  inputs:
    versionSpec: 5.0.0

- task: NuGetCommand@2
  displayName: 'NuGet restore'
  inputs:
    restoreSolution: '$(Parameters.solution)'

- task: VSBuild@1
  displayName: 'Build solution'
  inputs:
    solution: '$(Parameters.solution)'
    msbuildArgs: '/p:DeployOnBuild=true /p:WebPublishMethod=Package /p:PackageAsSingleFile=true /p:SkipInvalidConfigurations=true /p:PackageLocation="$(build.artifactstagingdirectory)\\"'
    platform: '$(BuildPlatform)'
    configuration: '$(BuildConfiguration)'

- task: VSTest@2
  displayName: 'Test Assemblies'
  inputs:
    testAssemblyVer2: |
     **\$(BuildConfiguration)\*test*.dll
     !**\obj\**
    platform: '$(BuildPlatform)'
    configuration: '$(BuildConfiguration)'

- task: PublishSymbols@1
  displayName: 'Publish symbols path'
  inputs:
    SearchPattern: '**\bin\**\*.pdb'
  continueOnError: true

- task: PublishBuildArtifacts@1
  displayName: 'Publish Artifact'
  inputs:
    PathtoPublish: '$(build.artifactstagingdirectory)'
    ArtifactName: '$(Parameters.ArtifactName)'