title: Failed to build: Error parsing reference: "microsoft/dotnet:2.1-runtime AS base" is not a valid repository/tag:
body: <p>I got the below error when build docker for console application using .net core.</p>
  
  <blockquote>
    <p>Step 1/15 : FROM microsoft/dotnet:2.1-runtime AS base
    Error parsing reference: "microsoft/dotnet:2.1-runtime AS base" is not a valid repository/tag: invalid reference format</p>
  </blockquote>
  
  <p>My Dockerfile looks below </p>
  
  <pre><code>FROM microsoft/dotnet:2.1-sdk AS build
  WORKDIR /src
  COPY ConsoleApp2/ConsoleApp2.csproj ConsoleApp2/
  RUN dotnet restore ConsoleApp2/ConsoleApp2.csproj
  COPY . .
  WORKDIR /src/ConsoleApp2
  RUN dotnet build ConsoleApp2.csproj -c Release -o /app
  
  FROM build AS publish
  RUN dotnet publish ConsoleApp2.csproj -c Release -o /app
  
  FROM base AS final
  WORKDIR /app
  COPY --from=publish /app .
  ENTRYPOINT ["dotnet", "ConsoleApp2.dll"]
  </code></pre>
  
  <p>My docker version is </p>
  
  <blockquote>
    <p>Docker version 17.03.1-ce-rc1, build 3476dbf</p>
  </blockquote>
  
  <p>Can some one suggest what I am doing wrong in this.
  Thanks in advance.</p>