Keep getting "Unable to publish GPT" error

Creating custom GPT, which handles a short dialog with user and then generates links to my website with params, user specified during chatting. Link is send to user . It is subdomain linke like subdomain.site.com . Somewhy keep getting the error below, despite the subdomain was already added and veriefied with TXT record in Setting > Account > GPT builder profile

What I miss?