Im unable to add ui as a subdomain

The issue is, i have hosted a next js website on cloudflare pages, and i added a domain for it which is ui.hextastudio.in now the issue is the when I had to ui.hextastudio.in it gives errors in browser console where it says some files are missing in build but the build logs are perfectly fine. now when i open same website but using pages.dev domain it doesn’t give any error infact if i add other domain hi.hextastudio.in it works fine! only that ui.hextastudio.in isn’t working.

Additionally, the domain shows that its Inactive(Error)

Hello,

Are you seeing any error codes/messages along with it on your dashboard when you try to add the subdomain?