This error can occur for two reasons:
- The "backorder by" date has lapsed on an active backorder, and it's too late for you to add the domain to your backorder list. You will not be able to participate in this domain auction.
- If a domain has already gone through the "Pre-Release" cycle and there is an auction pending or in progress (or there were no backorders), you will not be able to add it to your backorder list for 7 days.
If the domain has gone through the Pre-Release cycle and is not sold, when the registrar deletes the domain it will then enter the Registry Redemption Period and subsequent Pending Delete cycle.
When you attempt to add the domain in another week, it will be added to your backorders as a Wish List item. Should the domain become available again in the future (such as during Pending Delete), you will be notified via email.