Error Getting certificate for mail.ispf.gov.ua

… Submitting the ACME challenge for dns:mail.ispf.gov.ua for verification.
Waiting for the order status to update… 0
Error: The challenge did not complete.

            Host Name: mail.ispf.gov.ua
            Error Code: 403
            Error Type: urn:ietf:params:acme:error:unauthorized
            Error Detail: Invalid response from http://mail.ispf.gov.ua/.well-known/acme-challenge/cAonMdmUp9tVw5mQX33ATQzqjqhOER1_Sd2lTMAg9Bs [62.80.187.78]: "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\r\n<html xmlns=\"http"

This is a critical error, the script will now stop.
Information obtained from the following URLs: https://acme-v02.api.letsencrypt.org/acme/authz-v3/3410463600

Hi @ispf.gov.ua

please answer all the questions of the template you have seen.