domain is returning a DEPLOYMENT_NOT_FOUND error

I purchased the domain docvaultpro.com and am trying to add it to my project but I’m getting the error ‘This domain is linked to another Vercel account.’ I have added the TXT verification record at _vercel.docvaultpro.com and it has fully propagated (verified on dnschecker.org) but the domain still won’t verify. Please release this domain from the previous account so I can connect it to my project. My project is docvault under account Boringsite

see image attached, What does this mean?