Problem with subdomain

Hello,
I have a problem, it must be done 10 times that I try to reinstall gitlab so that it works only with the subdomain. and we the main domain. For that I created a DNS rediction in A. I changed the variable external_url (“https://git.neturo.fr”)
But I got errors from letsencrypt

I tried to follow several tutorials but nothing worked.
Did I forget anything?
In the gitlab.rb I modify the variable

  • External URL
    -letsencrypt [‘enable’] = true
  • letsencrypt [‘contact_emails’] = [‘admin@neturo.fr’]

Here is the last tutorial I followed https://linuxize.com/post/how-to-install-and-configure-gitlab-on-ubuntu-18-04/