Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Thunderbird doesn't trust a valid CA Certificate

  • 2
  • 1 nwere nsogbu anwere nsogbu a
  • 38 views
  • Nzaghachi ikpeazụ nke christ1

more options

So basically I sent a digitally signed email using a certificate issued by Sectigo RSA Client Authentication and Secure Email CA.

Now the recipient of the email replied to me with a certificate issued by COMODO RSA Client Authentication and Secure Email CA, but it says the Digital Signature is invalid? Why is it invalid?

I got an error when I try to reply back with a digitally signed and encrypted email:

Sending of the message failed. You specified encryption for this message, but the application failed to find an encryption certificate for johndoe@gmail.com

What I have tried so far:

Exported the .crt then import it on "Manage Certificates" People's Tab

But still got an error when trying to reply to the email

So basically I sent a digitally signed email using a certificate issued by Sectigo RSA Client Authentication and Secure Email CA. Now the recipient of the email replied to me with a certificate issued by COMODO RSA Client Authentication and Secure Email CA, but it says the Digital Signature is invalid? Why is it invalid? I got an error when I try to reply back with a digitally signed and encrypted email: Sending of the message failed. You specified encryption for this message, but the application failed to find an encryption certificate for johndoe@gmail.com What I have tried so far: Exported the .crt then import it on "Manage Certificates" People's Tab But still got an error when trying to reply to the email

All Replies (2)

more options

Here's a screenshot, it doesn't trust COMODO CA

more options

Please stick to your original topic at https://support.mozilla.org/en-US/questions/1250241