Set up CAA
Having a CAA record in your DNS for Comodo, Let’s Encrypt won’t overwrite with a Let’s Encrypt certificate. Speaking in general terms, CAA secures for a correct certificate authority.
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 issue “letsencrypt.org”
Comodo:
CAA 0 iodef “mailto:abuse@example.com”
CAA 0 issuewild “comodo.com”
DirectAdmin as name server:
Configure in directadmin.conf with dns_caa=1.