Defender blocking www version of site URL

Defender appears to be blocking the www version of the site URL, even after it has been deactivated & deleted, and all caches have been cleared. The site in question is: https://openfax.com/ Trying to access either http://www.openfax.com/ or https://www.openfax.com/ results in Defender's "The administrator has blocked your IP from accessing this website" lockout message.