Subject: [OAUTH-WG] OAuth Unsuccessful Response

From: Asghar Amereii <[email-masked]>
Date: Wed, 12 Jun 2019 14:42:34 +0430

According 
tohttps://www.oauth.com/oauth2-servers/access-tokens/access-token-response/

    Error responses are returned with an HTTP 400 status code (unless
    specified otherwise), with error and error_description parameters. The
    error parameter will always be one of the values listed below.

      * invalid_request
      * invalid_client
      * invalid_grant
      * invalid_scope
      * unauthorized_client
      * unsupported_grant_type

Can I have custom error like "invalid_captcha" or "captcha_required"?

I want , if some one send wrong credentials for 3 times , I send 
"captcha_required" error and for next time must send valid captcha code

My question is:

 1. Is it allowed to define custom error codes in OAuth ?
 2. Is there alternative way to solve my problem?