There are certain instances where a particular domain name may not be eligible or available to be backordered. Here are the most common reasons for a domain being unable to be backordered: 1 - The domain extension is not supported: At this time, we are only able to process backorders for domains with the following domain extensions: .com, .org, .net, .biz, .info, .co, .us, .me, and .mobi. A domain with a different extension type than these would not be available for backorder. 2 - A domain falls within the Single backorder policy: March 2009 was the first time that multiple backorders could be placed on a single domain. Before this date, only one domain backorder per domain was allowed at the time. So hypothetically, if you were trying to place a backorder on a domain that had a backorder effective prior to March 2009, you would not be able to do so because it would still be effective under the Single backorder policy. 3 - The domain is a Premium domain: If a domain name is considered to be a Premium domain name, it is not eligible for backorder at this time. Premium domain names are essentially short, catchy, memorable names that are already registered to another person, entity or organization. Premium domain names are often more expensive, with the demand for these names usually being significantly higher. 4 - The domain is blocked: There are a number of given reasons why a particular domain name might be blocked. But if is blocked, it is also ineligible for backorder.