Dedicated SSL Certificate with Custom Hostname Not Allowing secure forwarding

The client (located in DC) says even after hard refreshing, switching browsers, and using an incognito window, the site doesn’t load. Although it does load when accessing it a via cellular network in that DC office. The IT person in the office rebooted their firewall but doesn’t see any indications that it’s causing the issue. This is the response he sees from the site:

Request URL: https://www.promundoglobal.org/
Request Method: GET
Status Code: 403
Remote Address: 18.220.250.87:443
Referrer Policy: no-referrer-when-downgrade
Response Headers
content-encoding: gzip
content-type: text/html; charset=iso-8859-1
date: Thu, 13 Dec 2018 00:28:30 GMT
server: Pagely-ARES/1.3.20
status: 403
vary: Accept-Encoding
Request Headers
:authority: www.promundoglobal.org
:method: GET
:path: /
:scheme: https
accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,/;q=0.8
accept-encoding: gzip, deflate, br
accept-language: en-US,en;q=0.9
cache-control: max-age=0
upgrade-insecure-requests: 1
user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36