Getting error when publishing webAPI to Azure

I built my first API and am trying to publish to Azure.

I get the following error "Be sure that the Startup.cs for your application is calling AddSwaggerGen from within ConfigureServices in order to generate swagger file. Visit https://go.microsoft.com/fwlink/?LinkId=2131205&CLCID=0x409 for more information."

Failed to generate swagger file. Error dotnet swagger tofile

Here is my code from Startup.cs:

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "PeopleSearch v1"));
            }

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}

Does anyone know what I am doing wrong?