startup class in a plugin at Nop 4.40 not called up

I added the startup class in nopcommerce version 4.40 following is the code but its not called.

public class RedirectUrlStartUp : INopStartup
    {
        /// <summary>
        /// Configure the using of added middleware
        /// </summary>
        /// <param name="application">Builder for configuring a n application's request pipeline</param>
        public void Configure(IApplicationBuilder application)
        {
        }

        public void ConfigureServices(IServiceCollection services, IConfigurationRoot configuration)
        {
            throw new NotImplementedException();
        }

        /// <summary>
        /// Gets order of this startup configuration implementation
        /// </summary>
        public int Order =>  900;
    }