You can resend the invitation: In "Buyer Management", find the buyer and click "Resend Invitation" in the action menu on the right. Alternatively, open the buyer's detail page and click "Send Invitation" in the invitation status section. Another option is to "Copy Invitation Link" and send it directly via email or instant messaging, so the buyer can complete the invitation process by clicking the link. If the problem persists, please verify that the buyer's email address is correct.