Hello @andredane,
The 504 Gateway Timeout Error you have encountered indicates that the server could not complete the request sent by your browser in time and th. In this particular case, it appears that something is interfering with the Security Optimizer plugin and the requests sent by it are being blocked. As per the provided error message you have also encountered:
COULD NOT CONNECT TO THE WORDPRESS REST API: Either a security plugin, custom function, or rules in your .htaccess file is preventing the WordPress REST API from working properly. SiteGround Optimizer is using it to store its options and other functionalities so please make sure it works properly.
The issue is likely caused by a different security plugin or restrictive htaccess rules. If you have any other third-party plugins installed on your website, please try to temporarily disable them and see if that helps.
If that doesn’t resolve the issue, then the best course of action would be to get in touch with our support team if you are a SiteGround client. This will allow us to review your website in detail and pinpoint what exactly is interfering with the Security Optimizer’s functionalities.
Best Regards,
Preslav Kenanov