Conflict with security plugin?

Hello, I’m having a recurring issue on a site that uses your caching tool and a security plugin to hide the wp-admin login page. This has been happening sporadically for months. Once logged in when the page redirects to wp-admin, the user gets a

FORBIDDEN
You do not have permission to access this document.
Web Server at (domain.com)

However, when you then visit the homepage, it shows that you were successful logged in and you can access the backend dashboard just fine.

When I check the error logs, it is throwing an apache error re the caching plugin and Redis in the error logs: 

mod_fcgid: stderr: W3TC\\Cache_Redis::_get_accessor: Connection refused, referer: https://www.cyca.org/wp-admin/plugins.php

I have tried clearing the cache and I’ve added a bunch of exclusions to the page cache and browser caching rules as follows:

/wp-admin/
index\.php
wp-.*\.php
wp-admin

The issue resolves itself temporarily but always inevitably returns. Have you had this issue before? We are using All-in-One Security plugin to hide the login page.

Please advise? Here is a screen recording demonstrating the issue:

https://drive.google.com/file/d/1Fc_0M-xysiocwB0v65g1bk-9v9vx1fre/view?usp=sharing