Expert WordPress/Opencart Developer Required

Having issues with our website, the login function is not working. See overview of issue here: the login is failing at the OpenCart REST API authentication stage. The relevant server log entries show: The login page /login/ is successfully loading with HTTP 200. Multiple requests to the OpenCart REST API token endpoint are returning HTTP 400: POST /opencart/index.php?route=feed/rest_api/gettoken&grant_type=client_credentials The subsequent OpenCart REST login request is returning HTTP 401: POST /opencart/index.php?route=rest/login/login For example, at 02/Sep/2026 16:53:28 +1000, the server recorded: POST /opencart/index.php?route=rest/login/login HTTP/1.1" 401 with the preceding token requests repeatedly returning 400. This confirms that the requests are reaching and being processed by the server; we are not seeing a server-level connection or access block causing the login failure. The issue appears to be with the OpenCart REST/OAuth2 authentication implementation, specifically the token generation/client credentials or related application configuration. Please have your developer review the OpenCart application located at: /home/topideac/shop.topidea.com.au/opencart/ They should specifically check the custom REST/OAuth2 login implementation, API client credentials, token generation, and related configuration.