If you are referring to 1.1.1.1 as DNS resolver, regardless if this site is or was on cloudflare: it has nothing to do with User Agents. This issue is related to the site / update process or whatever.
. Here i got success if I send it with an User-Agent and the redirect isn’t in use. So something changed because everything with an user-agent does work but if we send no user-agent we get 403.