Either the website is stopped or the requested domain name is not configured for any website:
https://vivid.shop.csu.edu.au:443/Login?returnurl=%2f&_cldee=bXdlc3Rlcm1hbkBjc3UuZWR1LmF1&recipientid=contact-99d5f75ed94ae911a971000d3ad1c598-34d7ac8d69e94766a2cc19a4e23747e4&esid=3ce2ebdb-345b-e911-a84c-000d3a6a0363
If you're an administrator of this site, you need to go to
Sites
and make sure the following domain name is configured either in the site properties or a domain alias of a running web site:
vivid.shop.csu.edu.au:443