I cannot make previews of my articles: Error 403

I have installed WP Cerver and it looks great, but when I try to preview an article before publishing it, it returns the following error:

Sorry, you do not have permission to continue.
Your request seems suspiciously similar to automated requests from spam publishing software or has been denied by a security policy configured by the web administrator.

If you think you should be able to make this request, please let us know.

I have done a search for the RID and it is associated with IP 0.0.0.0.0 with the message: Malicious Response Denied IP address is blocked.

Is there any way to add an exception for pages containing “&preview=true&_thumbnail_id=”? The full page string starts and ends with numbers:
https://www.samplepage.com/?p=428144&preview=true&_thumbnail_id=428261

Thanks,