Cannot set up swagger in blazor app

using BlazorImdb.Server.Services;
using BlazorImdb.Server.Interfaces;
using BlazorImdb.Server.Models;
using Microsoft.AspNetCore.ResponseCompression;
using Microsoft.EntityFrameworkCore;



var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
//Donot forgot to add ConnectionStrings as "DefaultConnection" to the appsetting.json file
builder.Services.AddDbContext<DatabaseContext>
    (options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));
builder.Services.AddTransient<IUser, UserManager>();
builder.Services.AddTransient<ICategory, CategoryManager>();




builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

app.UseSwaggerUI();

builder.Services.AddControllersWithViews(); //Exception Unhandled System.InvalidOperationException: 'Cannot modify ServiceCollection after application is built.'
builder.Services.AddRazorPages();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseWebAssemblyDebugging();
}
else
{
    app.UseExceptionHandler("/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}
app.UseSwagger();
app.UseHttpsRedirection();
app.UseBlazorFrameworkFiles();
app.UseStaticFiles();
app.UseRouting();
app.MapRazorPages();
app.MapControllers();
app.MapFallbackToFile("index.html");
app.Run();