Enigmail 2.0.7 with TB 52.9.1 and GnuPG 2.2.8 can not find my private key SOMETIMES

[Lev A. Serebryakov]

I have Enigmail 2.0.7 and GnuPG 2.2.8 installed, and SOMETIMES Enigmail
can not find my private key to sign message.

What is puzzling, that it depends on RECEPIENT address. It always
happens when I send message to some mailing-list!

It shows message:

===
Sending of message failed
You specified that this message should be digitally signed, but
application failed to find the signing certificate specified in your
Mail & Newsgroup Account Settings, or certificate has expired.
===

I've read this: https://enigmail.net/index.php/en/faq?view=topic&id=14

And I don't have "parseErrorOutput: status message" in my debug log at
all even right after I got this error!

Often I'm shown passphrase dialog (from gpg-agent) and everything works
as intended, but sometimes not.

--
// Black Lion AKA Lev Serebryakov

[Patrick Brunschwig]

The message you are getting is realted to S/MIME. It looks to me like you have/had an expired or otherwise invalid S/MIME certificate. Enigmail would try to activate OpenPGP or S/MIME depending on your configuration as explained in the following FAQ entry of the handbook: https://enigmail.net/index.php/en/user-manual/handbook-faq#prefer_smime_vs_openpgp

[Lev A. Serebryakov]

I don't have S/MIME certeficate at all, only GnuPG/OpenPGP key.

And it works most of times. But sometimes something triggers and it shows this error. Maybe, it depends on Recepient address, it is triggered by FreeBSD mailing lists very often (but not always!). Also, when it is triggered, it prevents to auto-save drafts as I have "Encrypted drafts" option enabled and it complains that it could not encrypt it.

Unfortunately, I can not construct 100% reproducable scenario.

I have "Use PGP/MIME bt default" and "Prefer Engmail (OpenPGP)" settings selected in account preferences.

[Lev A. Serebryakov]

Also, I have pinned ("Use specific OpenPGP key ID:") key for this account to avoid selection of my old key.

[Roger Wang]

I have the same issue. My setting is sign by default and never encrypt. The interesting thing is: if I toggle on and off the encrypt button, then the signing operation succeed without the error.

[Lev A. Serebryakov]

Yes, «toggle on and off the encrypt button» helps me too!
Looks like this bug is connected to e-mail used to create message (I have 4 e-mails for my account and 4 IDs for key — lists of addresses in Thunderbird and Key are equal).

[Roger Wang]

btw, it seems to be 100% reproducible here.

[Roger Wang]

I attach my log here. The first failed try is on 10:59, after toggle on/off encrypt button, it succeeded on 11:00.

[Olav Seyfarth]

I experienced similar issues here, still investigating to pin the cases down:
I have a receipient's key but the message is not encrypted to it, auto-encrypt doesn't trigger.
Yet, sending UNENCRYPTED (according to lock button status) yields "no key from receipient".