If your registration status is Pending, that means that the Auction House has not approved or declined your registration request.
The Auction House could have reached out to you to request additional information before they make a decision. Make sure to check Alerts (browser) or Messages (app) for any messages from the Auction House.
If your registration is still pending or declined, at least 24-48 hours prior to the start of the auction, you can reach out to the Auction House to ask if they need additional information from you to approve your registration. Just click the "ASK A QUESTION" link on the listing or catalog.