Set up CAA
CAA records in your DNS restrict which CA can issue a certificate for this domain name.
Explanation:
https://blog.qualys.com/ssllabs/2017/03/13/caa-mandated-by-cabrowser-forum
https://sslmate.com/caa/
Let’s Encrypt:
CAA 0 iodef “mailto:abuse@example.com”
CAA 0 issuewild “letsencrypt.org”
ZeroSSL:
CAA 0 iodef “mailto:abuse@example.com”
CAA 0 issuewild “sectigo.com”
Comodo:
CAA 0 iodef “mailto:abuse@example.com”
CAA 0 issuewild “comodo.com”
DirectAdmin for name server settings:
Configure directadmin.conf with dns_caa=1.