Bearer token doesnot pass on swagger - asp.net-core

Question

I am trying to implement OAuth2 ClientCredentials flow on ASP.NET CORE 3.1. I follow guidelines on the official GitHub repo.
The problem is regarding getting bearer token on Swagger-UI. It doesn't pass automatically. I investigated the issue on Swashbuckle Github repo. There are some closed issues. There's no solution.
Below my implementation :
public static class SwaggerExtensions
{
public static IServiceCollection EnableSwagger(this IServiceCollection services)
{
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo { Title = "Sample API", Version = "v1" });
c.AddSecurityDefinition("oauth2",
new OpenApiSecurityScheme
{
Type = SecuritySchemeType.OAuth2,
Flows = new OpenApiOAuthFlows
{
ClientCredentials = new OpenApiOAuthFlow
{
TokenUrl = new Uri("/api/auth/token", UriKind.Relative),
Scopes = new Dictionary<string, string>
{
{ "readAccess", "Access read operations" },
{ "writeAccess", "Access write operations" }
},
}
},
Name = "Authorization",
In = ParameterLocation.Header,
Scheme = "Bearer"
});
c.AddSecurityRequirement(new OpenApiSecurityRequirement
{
{
new OpenApiSecurityScheme
{
Reference = new OpenApiReference { Type = ReferenceType.SecurityScheme, Id = "oauth2" }, Name = "oauth2"
},
new[] { "readAccess", "writeAccess" }
}
});
c.OperationFilter<OAuth2OperationFilter>();
});
return services;
}
public class AuthenticationAttribute : Attribute, IAsyncAuthorizationFilter
{
public async Task OnAuthorizationAsync(AuthorizationFilterContext context)
{
bool isAnonymousAllowed = context.Filters.Any(f => f.GetType() == typeof(AllowAnonymousFilter));
if (isAnonymousAllowed)
{
return;
}
if (!context.HttpContext.Request.Headers.TryGetValue("Authorization", out var authHeaderValue))
{
throw new UnauthorizedAccessException("A valid key must be supplied");
}
string authHeader = authHeaderValue.ToString();
if (string.IsNullOrEmpty(authHeader))
....
}
}
After creating an access_token, I cannot get this token on another controller on Swagger-UI.
Swashbuckle.AspNetCore version -> 5.5.1
Swashbuckle.AspNetCore.Swagger -> 5.5.1