Why can't I use my custom domain as the Primary URL?
Actually, you can use a custom domain in the Primary URL but you must be sure to include a valid link ID with it, such as the link ID `/movies` in this URL:
`http://$linkdomain/movies`
Because the link ID `/movies` follows the custom domain `$linkdomain/`, ClickMagick knows exactly where to redirect incoming clicks to.
The problem occurs when you don’t include a link ID:
`http://$linkdomain`
Without a link ID, ClickMagick doesn’t know where to redirect clicks to, creating an error condition.
Very simply, if you’re going to use a custom domain in the Primary URL of a tracking link, make sure that you remember to include a link ID so that ClickMagick knows exactly where to redirect incoming clicks.
If you’re unsure about what a link ID is or why you need one, we have an FAQ that will walk you through the steps for creating a tracking link:

|  | How do I set up a very basic tracking link?