Improve bulk-email deliverability with a separate link- and image-domain

Description:

All links in mailings are currently sent/hosted with a microsoft domain. Depending on how the images are integrated, they also refer to different domains.

If Microsoft allows to integrate a separate link- & image-domain that matches with the sender domain (TXT-entries linked to Microsoft), E-mail providers rate this positively and the deliverability of the mailings is also increased.