Troubles adding TXT record to verify domain

Hello! I’m trying to verify my domain with GitLab Pages, but ran into a bit of trouble when adding the TXT record on domain.com. I was able to successfully add the CNAME record for my subdomain, but when trying to add the TXT record to verify the domain, it won’t let me add it. It will let me add it if I just use the subdomain, but when I try to add it for _gitlab-pages-verification-code.subdomain, the button to add it goes gray. I’m not sure if others have had this problem, or if this is even the right place (maybe I need to get support from domain.com?) but I figured I would ask here in case anyone had any answers.