How to edit Allowed From Hostnames

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Hello,

We've recently discovered a section labeled "Allowed From Hostnames" displayed at the bottom of the Email Defaults page. This section currently lists all the Eloqua subdomains configured in the instance, including the out-of-the-box ones. However, there doesn't seem to be an option to edit this list. The list of subdomains is also found connected with our OIC integration. Does anyone know how this section was generated and how to add or remove subdomain(s) on this list?

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