Disable the Avast mail scanner and then things might work. It is incredible the number of folks with Avast that appear in these forums complaining that some feature of mail does not work, and when avast is removed everything starts working.

You will note the certificate Eudora complains about is issued by Avast, not a certifying authority. See Wikipedia for a description of what a certifying Authority is. https://en.wikipedia.org/wiki/Certificate_authority. Not Avast that is for sure.

See also https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#AVAST

Thank you Matt. How can I find the Avast mail scanner? When I open Avast, I find lots of features, but the only scanner I find is "virus scans." I don't think that's it.

What do I look for?

Arden

Hi That would be a question for the Avast forum. Try this answer - https://forum.avast.com/index.php?topic=230743.0

Thank you Agnes - that might help! I'll give that a try.

I appreciate your help. Stay safe and virus-free.

Arden

This may help...Disable Avast Mail Shield:

• https://help.avast.com/en/av_free/19/settings_sh_mail_basic.html

Thanks. I disabled the Avast mail shield, but the problem persists. Outgoing mail works OK on my web client, (Earthlink, Mozilla), but not on mail management software - either Thunderbird or Eudora.

This just started recently.

Thunderbird gives me this:

An error occurred while sending mail. The mail server responded: 554 5.7.1 <[email address]>: Relay access denied. Please check the message recipient "[email address]" and try again

Eudora gives me this:

SSL certificate rejected - unknown error

Certificate:

   Data:
       Version: 3 (0x2)
       Serial Number:
           6e:5d:32:71:32:b8:bb:48:98:9d:7a:ca:6c:42:f6:66
       Signature Algorithm: sha256WithRSAEncryption
       Issuer: OU=generated by avast! antivirus for SSL/TLS scanning, O=avast! Web/Mail Shield, CN=avast! Web/Mail Shield Root
       Validity
           Not Before: Jan  1 12:00:00 2010 GMT
           Not After : Jan  1 12:00:00 2040 GMT
       Subject: OU=generated by avast! antivirus for SSL/TLS scanning, O=avast! Web/Mail Shield, CN=avast! Web/Mail Shield Root
       Subject Public Key Info:
           Public Key Algorithm: rsaEncryption
           RSA Public Key: (2048 bit)
               Modulus (2048 bit):
                   00:e7:10:94:e9:d4:21:2b:76:38:34:a7:a7:3b:4e:
                   a7:92:94:e1:e6:46:72:14:85:2d:18:cd:55:c8:30:
                   73:1e:f2:51:1e:73:c6:2f:6c:36:96:e9:cb:1e:56:
                   92:c8:d8:15:85:4c:e4:65:8b:7b:27:1b:e0:84:9d:
                   97:9f:40:de:b2:f0:8d:6c:01:92:8a:fc:b6:62:d6:
                   48:e4:22:d5:fd:99:3a:f9:a3:33:fb:fa:7c:58:07:
                   55:9f:19:ff:9f:3a:64:dd:bd:07:d2:ed:bc:39:20:
                   51:bf:fe:ca:60:e0:cd:b1:71:d9:54:a7:ba:d1:8e:
                   d0:a0:1c:1b:d3:0c:98:05:79:d7:b1:d2:80:4b:a0:
                   c8:e2:e2:64:80:dd:58:af:d6:7c:9a:66:b0:83:b3:
                   19:76:ab:5f:ad:a6:27:3f:f1:f4:6e:72:dc:47:c0:
                   4d:b7:2a:c0:be:65:6f:3f:73:fd:4e:28:ab:e6:8c:
                   20:4b:6c:32:ce:00:bd:45:7a:1e:fa:d9:b7:57:0d:
                   5a:89:31:34:fe:22:78:8b:56:eb:57:f6:c0:e6:8d:
                   44:f1:7e:a5:2e:3c:7d:f3:ef:82:95:69:a9:6f:5d:
                   fb:e6:e2:dc:b3:1f:91:ce:20:a0:bc:b3:05:3a:8c:
                   98:61:2e:06:9e:28:cd:02:73:ae:34:0d:cb:1f:67:
                   f1:41

What to do?

Thanks!

Email address removed. Do not post sensitive information in a public forum. See Mozilla Support rules and guidelines

hi Since there is a problem with both mail clients, and no problem with webmail, the problem must stem from something in your local computer setup. Answers that are related to just Thunderbird or just Eudora will not help. You said you had disabled Avast email scanning, yet the second example of the error still comes from Avast. It seems your Avast scanning was not truly turned off. Please try again - set Avast not to scan email, turn off TLS/SSL scanning in Avast. Make sure you close and open Thunderbird and Eudora before retrying. If you still get an error from Avast, and you carefully followed the steps for stopping mail scanning, then try asking on Avast forum why it won't turn off. One simple but unlikely thing to test - does your computer have the correct current date - including year? I have run into that once or twice where the computer time is outside the certificate start/end dates.

Correction - if this affects local email clients, it could also be the communication between your email client and your email provider's servers. However we seem to have an error clearly from Avast, so that is the likely culprit.

Thanks Agnes. I'll try again to disable Avast mail checking.

It's not just one computer, the same thing started happening at the same time with my wife's computer, which uses Eudora rather than Thunderbird.

Thanks again for the help!

Arden

Ah - two separate machines and two email clients. Both machines using Avast? Using two separate email addresses? Both using the same email provider? Nice test setup!

Ok, not sure this will help but here is something about Avast and invalid certificates. I would not necessarily add a certificate to Thunderbird right away - but step 8 of the instructions for Thunderbird near the end of this page also mentions how to find and delete any old added certificates... https://support.avast.com/en-ca/article/Troubleshoot-invalid-email-certificate Try getting to the advised place in Thunderbird and see if there is an Avast certificate listed there, that perhaps just expired. Delete any Avast certificates you find on one of your machines and see if that changes anything.

I turned off all mail settings - mail shield, in/out bound scans, attachment scans. Couldn't find TLS/SSL. Cycled Thunderbird off/on. Same problem.

I'll check for old certificates.

Arden

Nothing in certificate manager about Avast - only DigiNotar.

Oh there's a blast from the past. Go Google DigiNotar certificates hack ... even WikiPedia it... OK, so that entry is probably in Thunderbird specifically to UN-trust DigiNotar, or block that certificate authority from ever being trusted, I hope so anyway. Alternatively if either machine has Windows 10 - disable Avast entirely (no need to uninstall) and enable Defender as your antivirus. See if that helps. If not - I'm out of suggestions...

Thanks for your patience! We have Win 7. Will defender or something equally good work?

I see there's a Defender for Win 7. I can try it.

Should I try Defender or MSE?

I'm no expert but MSE should work at least to test whether the error goes away.

I disabled Avast, installed MSE, rebooted Thunderbird. Same problem.

Frustrating!

re : Relay access denied

Are you using the correct outgoing smtp server for that email address?

Please post the following info:

In Thunderbird

• Help > Troubleshooting Information
• Locate 'Mail and News Accounts' section.
• Copy all that section and paste info into this forum question. Please do not edit anything.

I disabled Avast, installed MSE, rebooted Thunderbird. Same problem. Frustrating!

When you did this - did you test with EUDORA? That was the client that reported the error form Avast. If it fixed Eudora then the two problems are separate, and just happened to occur at the same time.