AdLinkFly allows you to user multiple domains when users shorten links.
All you need is to add the new domain as an alias/parked/cname domain to your main domain from your hosting control panel(Your hosting company can help you do this) then add the new domain to Admin Area >> Settings >> General >> Multi Domains
Please Note: Domains should be separated by a comma, no spaces. Make sure to remove the 'http' or 'https' and the trailing slash (/) so your new domains should look like domian1.com,domain2.com,domain3.com
If you want to set a different domain for the short links rather than the main domain, you can do this by navigating to Admin Area >> Settings >> General >> Default Short URL Domain also make sure to remove the "http" or "https" and the trailing slash (/)!. Example: domain.com