The type or namespace name 'StartUp' could not be found (are you missing a using directive or an assembly reference?)

The type or namespace name 'StartUp' could not be found (are you missing a using directive or an assembly reference?)

Process completed with exit code 1.

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.

This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.