The SDK 'Microsoft.NET.Sdk.Web' specified could not be found

The SDK 'Microsoft.NET.Sdk.Web' specified could not be found

Fresh Installation of
https://docs.microsoft.com/en-us/dotnet/core/tutorials/with-visual-studio-code
caused problems to mine by "The SDK 'Microsoft.NET.Sdk.Web' specified could not be found"

.NET Core runtimes installed:
Microsoft.AspNetCore.App 3.1.7
Microsoft.NETCore.App 3.1.7
Microsoft.WindowsDesktop.App 3.1.7

.NET Core SDKs installed:
3.1.401

VS Code:
VSCodeUserSetup-x64-1.48.0

May it's because I'm using Windows and previously used .net 3.1.4.?
But I uninstalled all properly (with Windows deinstalations) so after Restart and installatio of all like mentioned above, it shoud work, or? not even dotnet new mvc runs properly and was not able to run because The SDK 'Microsoft.NET.Sdk.Web' specified could not be found. Thx for Fixing These on newest Version.

^^lg