When a subscriber is using Hotmail, Yahoo!Mail or TDC Webmail, and marks your newsletter as "Junk", Ubivox receives a notification stating that a subscriber has "complained" about receiving the newsletter. The subscriber is then, automatically, suspended from the list. This guide elaborates complaints and how they are handled in Ubivox.
In some cases newsletters are not displayed properly in e-mail clients. This is due to the fact that e-mail clintes use different set ups. This guide elaborates why newsletter are not properly displayed.