URL redirects to Cox page

I've been accessing a specific URL fairly regularly while I'm not working (it's an employee site requiring two-step verification to sign in, which I do on a regular basis).

Lately I've been redirected to a Cox page site not found. My manager said the site is being blocked by Cox

I would like to find out how I can get this site whitelisted again. I need to continue using it pretty regularly, and the other employee portals I access are not experiencing the same issue.

Thanks.

EDITED to add: I've tried accessing through multiple browsers, reset all browsers, etc.