[build 4/6] RUN dotnet restore:
#11 1.033 Determining projects to restore...
#11 10.82 /src/backend.csproj : error NU1301: Unable to load the service index for source https://api.nuget.org/v3/index.json.
#11 18.49 /src/backend.csproj : error NU1301: Unable to load the service index for source https://api.nuget.org/v3/index.json.
#11 18.52 Failed to restore /src/backend.csproj (in 17.31 sec).
executor failed running [/bin/sh -c dotnet restore]: exit code: 1
ERROR: Service 'backend' failed to build : Build failed