Custom Domain for sGTM not working..

[FedericoMav]

See image, custom domain set and DNS CNAME updated, however when I debug my GTM server side container with the new domain, I get a "Error: Page not found
The requested URL was not found on this server." for the URL https://collect.38tera.com/gtm/debug?id=GTM-T36PBRFP&gtm_auth=R8x-Omn3y6WbtxG9AKtY4Q&gtm_preview=env...

What am I doing wrong