Hello. I get the error message pop-up when I try to send an encrypted email "Send Message Error: Sending of the message failed." Initially I had downloaded Kleopatra and Add-on Enigma, but then I found another article that said I didn't need this, so I did remove it, and I synced the key. Not sure if that messed up my settings... but I have restarted Thunderbird several times with add-ons disabled. The recipient of my email sent me his key and is verified. Also, the key setup on my end appears to be correct to me, per article https://support.mozilla.org/en-US/kb/openpgp-thunderbird-howto-and-faq. I've added some attachments. Let me know if anything else is needed. I appreciate your help. Yedid Mendoza