I tried but couldn't reproduce it any more. Therefore setting it to invalid.

Before making subtickets for each application: I wonder if it is not all Kleopatra anyway? Isn't the security approval dialog basically Kleopatra?

The equivalent for invalid S/MIME certificates are not-certified *PGP certificates.
(Valid/invalid are not ideal as technical terms as they have a broad general meaning, too. I hope my usage here is correct ;-) It is what I gathered from an explanation given by Werner.)

feedback of @mmontkowski needed

Invalid certs (as stated in the status column in Kleopatra) are mainly S/MIME certs (e.g. with missing root cert, CRL check failed, etc). I haven't seen invalid pgp certs yet (might be e.g. very old ones with missing self signature).

Invalid and expired are different cases.

Not a good idea. Because then the user will open it with the browser and the browser loads all kind of additional data including drive-by malware. If HTML *mail* is shown by a MUA no links should be followed to keep information and the fact that it was read confidential.

With signing only, the retry option is not offered and directly either hangs or shows the "Invalid CRL object" / "Unknown error" error.
Is this intentional?

In vsd 3.3.6 the option is now greyed out.

Moving smime encrypted/signed mails with attachments both works with drag&drop and via context menu on gpg4win-5.0.2-beta2 @ win11 with IMAP, so I'm setting this to resolved.

gpgol.log (call trace + data)

On gpg4win-5.0.2-beta-2 @ win11 i can reproduce:

• drag&drop does work
• move via context menu
  • works for selected mails
  • does not work for unselected mails

I can't resend the mail though.

Luckily I tested T5374: GpgOL: Can't move a signed mail in Outlook from In-Mail folder to any other folder afterwards and found out, that with my current settings in gpg4win-5.0.2-beta2 @ win11 I can reproduce this every time by sending signed only mails (pgp and smime does not matter).
Regarding my settings, I only activated the security dialog:

I have no idea how to reproduce this, there is no pattern. It could as well be, that some server side thing is involved, which is not under our control.
Either I'm lucky and it just happens while the logs are enabled, or I'll try some auto loop with appium one day.

I can't reproduce this on gpg4win-5.0.2-beta2 and vsd-3.3.4.