Problem with subdomain

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 (“”)
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’] = [‘’]

Here is the last tutorial I followed