as stated at https://certbot.eff.org/lets-encrypt/ubuntuxenial-apache
I did on:
| Distributor ID: | Ubuntu |
|---|---|
| Description: | Ubuntu 16.04.4 LTS |
| Release: | 16.04 |
| Codename: | xenial |
and all worked well 
at installation point
but When I go to site it doesn’t work 
I did restart apache2 server
in my apache I see two files:
000-default.conf 000-default-le-ssl.conf
I replaced real domain with example.com
000-default.conf
<VirtualHost :80>
# The ServerName directive sets the request scheme, hostname and port that
# the server uses to identify itself. This is used when creating
# redirection URLs. In the context of virtual hosts, the ServerName
# specifies what hostname must appear in the request’s Host: header to
# match this virtual host. For the default virtual host (this file) this
# value is not decisive as it is used as a last resort host regardless.
# However, you must set it for any further virtual host explicitly.
#ServerName www.example.com
ServerName test.domain.com
ServerAdmin webmaster@localhost
DocumentRoot /var/www/test/html/web/
<Directory /var/www/test/html/web>
AllowOverride None
Order Allow,Deny
Allow from All
php_flag display_errors On
Options -MultiViews
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.)$ app.php [QSA,L]
# Available loglevels: trace8, …, trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the loglevel for particular
# modules, e.g.
#LogLevel info ssl:warn
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
#Include conf-available/serve-cgi-bin.conf
RewriteCond %{SERVER_NAME} =test.domain.com
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
and for
000-default-le-ssl.conf
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
#Include conf-available/serve-cgi-bin.conf
Include /etc/letsencrypt/options-ssl-apache.conf
SSLCertificateFile /etc/letsencrypt/live/test.example.com/fullchain.pem
SSLCertificateKeyFile /etc/letsencrypt/live/test.example.com/privkey.pem