Netregistry doesn't allow AWS ACM cname validation records

I need to verify the ownership of the domain to validate the SSL certificate of the domain.

When I try to add the ACM CNAME validation records, I get an error from Netregistry console.

_*****109831*****.t***** is an invalid hostname

I read that the _ is a valid char in the DNS label

An underscore can appear in any place in a DNS label.

Any workaround to get rid of this problem