Sorry @k9mail@thunderbird but I moved to #FairEmail (Pro) due to its support to S/MIME and the certificate offered by my provider #Posteo.
Thanks to Marcel Bokhorst for FairEmail
@AAMfP@k9mail@thunderbird Interesting offer by #posteo. Just tried in #firefox on my #debian pc and it failed with "Action not permitted" when trying to download the files (I guess). I would also much prefer to upload my own CSR that I generated outside of the browser. BTW, in Germany #ausweisapp enables you to sign your PGP/GPG key by an official authority for free. OpenKeychain works nicely in #fairemail. #kudos to #dhl for using #smime to sign their mails.
@galvatron
I had the same problem and I thought it could've been that I'm using Mull and ReThinkDNS to block a gazillion trackers.
I really wanted to try it, so I ended up buying another certificate, but from desktop browser 😒 and it worked.
Now I have my S/MIME with #Posteo and #FairEmail