On Sat February 7 2026 10:27:37 dep via tde-users wrote:
| Since you're using IMAP which handles multiple clients well I suggest | you set up Thunderbird on the same box and see if it really does work | with Proton and if so see if you can drill down and find the difference | in how they behave.
Thanks. Installed Thunderbird. Forgot how much I utterly hate and despise Thunderbird. After an hour of remarkably colorful profanity, I've stopped poking around with it for now. Perhaps the mood to give it another try will return. At the moment it doesn't want to look at my main account but does want to tell me that the certificate for 127.0.0.1 has expired, which is kind of bizarre.
I too greatly prefer TDE KMail to Thunderbird. Nevertheless Thunderbird may have yielded a clue.
Do you have an installed, configured, and up-to-date certificate for the IMAP server side of your ProtonMail Bridge? If not, can you connect to it from Thunderbird and KMail with clear IMAP rather than encrypted IMAP? (This should be safe as it's entirely within the one box.)
--Mike