.NET 6 problem: Bearer error="invalid_token" error_description="The signature is invalid" in SwaggerUI

Question

I am currently trying to make authenticator when a specific user logs in and gets the weathercontroller information. It says that the jwt token is invalid.

So I have been using Angular 13 and .NET 6 asmy tech stack for the development of my project. Right now, .NET is my biggest problem. I can't comprehend or have a clue where to start fixing this error. I have seen a couple of YouTube videos, but none of them worked even in the slightiest way.

This is my code right now:

Program.cs

    using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using Microsoft.OpenApi.Models;
using System.Text;
using Swashbuckle.AspNetCore.Filters;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddHttpContextAccessor();
builder.Services.AddSwaggerGen(options => {
    options.AddSecurityDefinition("oauth2", new OpenApiSecurityScheme
    {
        Description = "Standard Authorization header using the Bearer scheme (\"bearer {token}\")",
        In = ParameterLocation.Header,
        Name = "Authorization",
        Type = SecuritySchemeType.ApiKey
    });

    options.OperationFilter<SecurityRequirementsOperationFilter>();
});
builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8
                .GetBytes(builder.Configuration.GetSection("AppSettings:Token").Value)),
            ValidateIssuer = false,
            ValidateAudience = false
        };
    });

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthentication();

app.UseAuthorization();

app.UseHttpsRedirection();

app.MapControllers();

app.Run();

My AuthController.cs:

using IdentityAndRoleAPI;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Security.Cryptography;

namespace IdentityAndRoleAPI.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class AuthController : ControllerBase
    {
        public static User user = new User();
        private readonly IConfiguration _configuration;

        public AuthController(IConfiguration configuration)
        {
            _configuration = configuration;
        }


        [HttpPost("register")]
        public async Task<ActionResult<User>> Register(UserDto request)
        {
            CreatePasswordHash(request.Password, out byte[] passwordHash, out byte[] passwordSalt);

            user.Username = request.Username;
            user.PasswordHash = passwordHash;
            user.PasswordSalt = passwordSalt;

            return Ok(user);
        }

        [HttpPost("login")]
        public async Task<ActionResult<string>> Login(UserDto request)
        {
            if (user.Username != request.Username)
            {
                return BadRequest("User not found.");
            }

            if (!VerifyPasswordHash(request.Password, user.PasswordHash, user.PasswordSalt))
            {
                return BadRequest("Wrong password.");
            }

            string token = CreateToken(user);
            return Ok(token);
        }

        private string CreateToken(User user)
        {
            List<Claim> claims = new List<Claim>
            {
                new Claim(ClaimTypes.Name, user.Username),
                new Claim(ClaimTypes.Role, "Moderator")
            };

            var key = new SymmetricSecurityKey(System.Text.Encoding.UTF8.GetBytes(
                _configuration.GetSection("AppSettings:Token").Value));

            var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256Signature);

            var token = new JwtSecurityToken(
                claims: claims,
                expires: DateTime.Now.AddDays(30)
                );

            var jwt = new JwtSecurityTokenHandler().WriteToken(token);

            return jwt;
        }

        private void CreatePasswordHash(string password, out byte[] passwordHash, out byte[] passwordSalt)
        {
            using (var hmac = new HMACSHA256())
            {
                passwordSalt = hmac.Key;
                passwordHash = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(password));
            }
        }

        private bool VerifyPasswordHash(string password, byte[] passwordHash, byte[] passwordSalt)
        {
            using (var hmac = new HMACSHA256(passwordSalt))
            {
                var computedHash = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(password));
                return computedHash.SequenceEqual(passwordHash);
            }
        }
    }
}

Weathercontroller.cs

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace IdentityAndRoleAPI.Controllers
{
    [ApiController]
    [Route("[controller]")]
    [Authorize]
    public class WeatherForecastController : ControllerBase
    {
        private static readonly string[] Summaries = new[]
        {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

        private readonly ILogger<WeatherForecastController> _logger;

        public WeatherForecastController(ILogger<WeatherForecastController> logger)
        {
            _logger = logger;
        }

        [HttpGet(Name = "GetWeatherForecast")]
        public IEnumerable<WeatherForecast> Get()
        {
            return Enumerable.Range(1, 5).Select(index => new WeatherForecast
            {
                Date = DateTime.Now.AddDays(index),
                TemperatureC = Random.Shared.Next(-20, 55),
                Summary = Summaries[Random.Shared.Next(Summaries.Length)]
            })
            .ToArray();
        }
    }
}

Please help!