Trying to re-use the domain we used on sandbox SC before refresh... The store domain name you chose 'xxxx' is already taken. Please go back and choose another. How do we unlock the domain to use it again? I've done this before, but can't remember how it is done. I should also point out that when I did it in the past, it was before we could use the same domain for both website and checkout.

I've had this issue in the past and I believe I redeployed a random domain name, then removed it and deployed the actual sandbox store domain name per a previous user's suggestion. I also had one instance where I left on vacation before resolving, and when I came back it just worked lol. If that doesn't work, might be support ticket worthy?

I do not know why it works but @Shelby Owens just shared the trick. netsuite

Thanks @Shelby Owens, this seems to get the record created with the old domain again, just waiting on my network guys to update the CNAME info now.