Whenever I try to add a custom domain into an app, it gives me this error. This domain conflicts with the existing base domain on another site. Please delete it from that site and try again. My custom domain is a fresh subdomain and it is not mapped anywhere else. Still, I am seeing this error. This is specifically for subdomains of marketcube.io, with all the other domains it is working fine.
This was working fine previously and I had added few domains which are working fine. But for the past few months, I am struggling with this issue.