I got a certificate for email encryption from Comodo. I have installed the certificate (from PFX file) in Thunderbird as described here. I have distributed the public key of the certificate an friends have sent mails encrypted with that public key.

But I can't read any encrypted mail. I have checked that the certificate is installed for the account. I have checked that the certificate is not expired. The signer of the certificate is Comodo:

CN COMODO SHA-256 Client Authentication and Secure Email CA
O  COMODO CA Limited

Comodo is listed in the certificate authorities tab with these entries:

Secure Certificate Services
COMODO ECC Certification Authority
Trusted Certificate Services
AAA Certificate Services
COMODO Certification Authority
COMODO RSA Certification Authority
COMODO RSA Client Authentication and Secure Email CA
UTN-USERFirst-Client Authentication and Email

Since Comodo is listed several times int the authorities tab I guess that each individual entry is important and necessary to accept a personal certificate. And the CN of the email certificate doesn't match any of the authorities names.

  • Is my guess right that these certs must match?
  • How can I add a Comodo (SHA-256 Client... Email CA) cert to Thunderbird?

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