Having trouble setting up subdomains

Hello all,

My domain is insulted.xyz and I'm trying to set up the subdomain esc.insulted.xyz but I'm having some trouble.

I've created a conf file:

root@ubuntu:/etc/apache2/sites-available# cat esc.insulted.xyz.conf
<VirtualHost *:80>
        ServerAdmin webmaster@insulted.xyz
        ServerName esc.insulted.xyz
        DocumentRoot /var/www/flarum/public

        <Directory /var/www/flarum/public>
            Options Indexes FollowSymLinks
            AllowOverride All
            Require all granted
        </Directory>

        <files xmlrpc.php>
            order allow,deny
            deny from all
        </files>

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

and enabled it with a2ensite, as well as set up an A record in the Linode DNS manager:
esc 45.79.213.234 Default

and when I wget esc.insulted.xyz locally, it returns the expected page, however, when attempting to access this domain remotely I see the error "DNS_PROBE_FINISHED_NXDOMAIN". Before adding the A record, my error was "ERR_NAME_NOT_RESOLVED".

What can I do to resolve this issue?