688E1D093C3638F588890D4450268311C7AD3F62

I had been using Thunderbird + Enigmail + Gpg4win + Yubikey to sign and encrypt my emails and the setup worked pretty well. However, after updating to Thunderbird 78, which has built-in OpenPGP support, I'm having trouble to configure it to work with my Yubikey. Following is my GPG keyring: PS C:\Users\DDoSolitary> gpg -K --keyid-format long C:/Users/DDoSolitary/AppData/Roaming/gnupg/pubring.kbx ------------------------------------------------------ sec# ed25519/50268311C7AD3F62 2017-09-02 [SC] 688E1D093C3638F588890D4450268311C7AD3F62 uid [ultimate] DDoSolitary <DDoSolitary@gmail.com> uid [ultimate] DDoSolitary <DDoSolitary@outlook.com> ssb> rsa4096/A7A1C4F99C807AD4 2019-03-21 [A] ssb> rsa4096/F091309F5863457C 2019-03-21 [E] ssb> rsa4096/90A79E1B71BC0CB1 2019-03-21 [S] The master key is kept offline and the subkeys are stored in my Yubikey and are used to sign/encrypt messages. What I've tried: 1. Enable "mail.openpgp.allow_external_gnupg" according to [https://wiki.mozilla.org/Thunderbird:OpenPGP:Smartcards https://wiki.mozilla.org/Thunderbird:OpenPGP:Smartcards] 2. Add my key ID to in the "End to End Encryption" section of Account Settings (I've tried key ID of the master key and the signing subkey, both of which don't work) 3. Write a new message, check "Security > Digitally Sign This Message", then click Send. I've checked that the GPGME library (C:\Program Files (x86)\GnuPG\bin\libgpgme-11.dll) is in the PATH environment variable. As Gpg4win only provides 32-bit builds, I also reinstalled the 32-bit version of Thunderbird. Unfortunately, I always get "Unable to send the message, because there is a problem with your personal key. The configured key ID 'xxx' cannot be found on your keyring."