AddVersionedApiExplorer not working in Asp.Versioning?

[Philxm]

Hi,

I have installed

1. Asp.Versioning.Mvc
2. Asp.Versioning.Mvc.ApiExplorer,

Also, I am using the following at the beginning of the code:

using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Mvc;
using Asp.Versioning;
using Asp.Versioning.ApiExplorer;
using Microsoft.OpenApi.Models;

However, it still shows Compiler Error CS1061 on AddVersionedApiExplorer below,

Can you help with any solution?

Thanks,

Phil