SERVFAIL looking up A for

[moh3n]

I get this error when I want to enable Letsencrypt on any domain.
Error: DNS problem: SERVFAIL looking up A for example.com

VESTA 0.9.8-20
installation : --nginx yes --apache yes --phpfpm no --named yes --remi yes --vsftpd yes --proftpd no --iptables yes --fail2ban yes --quota yes --exim yes --dovecot yes --spamassassin yes --clamav yes --softaculous yes --mysql yes --postgresql yes

[skamasle]

Domain resolv to your IP ?