JWTSetup.cs

var jwtSettings = new JwtSettings();
configuration.Bind(nameof(jwtSettings), jwtSettings);
services.AddSingleton(jwtSettings);

var tokenValidationParameters = new TokenValidationParameters
{
    ValidateIssuerSigningKey = true,
    IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(jwtSettings.Secret)),
    ValidateIssuer = false,
    ValidateAudience = false,
    RequireExpirationTime = false,
    ValidateLifetime = true
};

services.AddSingleton(tokenValidationParameters);

services.AddAuthentication(x =>
    {
        x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        x.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;
        x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    })
    .AddJwtBearer(x =>
    {
        x.SaveToken = true;
        x.TokenValidationParameters = tokenValidationParameters;
    });

 services.AddSwaggerGen(x =>
{
    x.SwaggerDoc("v1", new OpenApiInfo{ Title = "Tweetbook API", Version = "v1" });

    x.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
    {
        Description = "JWT Authorization header using the bearer scheme",
        Name = "Authorization",
        In = ParameterLocation.Header,
        Type = SecuritySchemeType.ApiKey
    });
    x.AddSecurityRequirement(new OpenApiSecurityRequirement
    {
        {new OpenApiSecurityScheme{Reference = new OpenApiReference
        {
            Id = "Bearer",
            Type = ReferenceType.SecurityScheme
        }}, new List<string>()} 
    });
});