Problema para instalar certificado

Hola estoi intentando instalar los certificados en mi plesk y me da este error

Mi dominio es:www.optimix.es
Imagen

Could not issue an SSL/TLS certificate for ziaruldesalaj.com
Details

Could not issue a Let's Encrypt SSL/TLS certificate for ziaruldesalaj.com . Authorization for the domain failed.

Details

Invalid response from https://acme-v02.api.letsencrypt.org/acme/authz-v3/26530907270.

Details:

Type: urn:ietf:params:acme:error:dns

Status: 400

Detail: DNS problem: NXDOMAIN looking up TXT for _acme-challenge.ziaruldesalaj.com - check that a DNS record exists for this domain