Cannot run swagger validator with localhost

Question

I need to run Swagger validator for a localhost, ex: url = http://localhost:8085. And I searched the way to do and follow: Can't read from file issue in Swagger UI and tried solution 3: Host the validator locally.

For: You will also need to tell swaggerui the location of the validator, where can I find: config.EnableSwagger().EnableSwaggerUi(c => c.SetValidatorUrl(<validator_url>));?

I updated my index.html (in my project) with:

 window.swaggerUi = new SwaggerUi({

 //url: "/um-api/swagger.json",

 url: parseUrl(),

 validatorUrl: "http://localhost:8080/validator", // added this line and seems it works

 dom_id: "swagger-ui-container",

I can run http://localhost:8080/validator/debug?url={site publicly accessible}/apiDocs , it works well.

But when I change to: http://localhost:8080/validator/debug?url=http://localhost:8085/apiDocs, it always return:

{"schemaValidationMessages":[{"level":"error","message":"Can't read from file http://localhost:8085/apiDocs"}]}

I see some note that online swagger ui will not work with locahost but is there anyway to fix this? I really need to run the validator with url = http://localhost:8085.

Many thanks!