while using restapi/oauth/token api with refresh token flow, we aRe getting token revoked error.

The problem I have faced is few of the api calls are errored {'error': 'invalid_grant', 'errors': [{'errorCode': 'OAU-211', 'message': 'Token revoked'}], 'error_description': 'Token revoked'} error.

There is no description about this error and I couldn't find any solution from the dev forum. We are not using any revoke api's, I was trying to figure out why token is getting revoked when I use ouath token api.