COMODO

Criar certificado intermediario

Arquivos do certificado recebido

AddTrustExternalCARoot
COMODORSAAddTrustCA
COMODORSADomainValidationSecureServerCA
MyDomain_com

Comando para gera certificado intermediario

cat MyDomain_com.crt COMODORSADomainValidationSecureServerCA.crt COMODORSAAddTrustCA.crt AddTrustExternalCARoot.crt > COMODO.ca-bundle

Verificação do SSL

https://www.sslchecker.com/sslchecker
https://www.ssllabs.com/ssltest/

Referencia

https://www.digitalocean.com/community/questions/how-to-install-positivessl-on-wordpress-from-start-to-finish