Error While running Angular application

I created my first application using Angular and when I try to run it I am getting below error

otnet: C:\Program Files\dotnet\sdk\3.1.201\NuGet.targets(124,5): error : Unable to load the service index for source https://api.nuget.org/v3/index.json. [E:\Users\0ixalli\Documents\server\project.csproj]
C:\Program Files\dotnet\sdk\3.1.201\NuGet.targets(124,5): error : Response status code does not indicate success: 407 (Proxy Authorization Required). [E:\Users\0ixalli\Documents\server\project.csproj]

I am new to donet, am I missing any install

Hi @Indira_Allika,

It seems that you are behind proxy and the NuGet cannot reach the server. Check this thread for more info:
https://stackoverflow.com/questions/9232160/nuget-behind-a-proxy