Private key not found when decrypting mail
Once in a while I receive a message I cannot decrypt. The console output looks like this:
% thunderbird
[ImapModuleLoader] Using nsImapService.cpp
ATTENTION: default value of option mesa_glthread overridden by environment.
ATTENTION: default value of option mesa_glthread overridden by environment.
2024-05-09 06:01:47.109369342 UTC: sequoia-octopus: rnp_load_keys: Your Thunderbird is using Sequoia's Octopus, version 1.8.1
(sequoia-openpgp: 1.19.0). For details, and to report issues please
see https://gitlab.com/sequoia-pgp/sequoia-octopus-librnp .
2024-05-09 06:01:47.109402489 UTC: sequoia-octopus: rnp_load_keys: Your Thunderbird profile appears to be: "/home/jan/.thunderbird/jguydki6.Development User"
console.debug: "Found 4816 public keys and 44 secret keys (44 protected, 0 unprotected)"
console.debug: "Successfully loaded optional OpenPGP library libgpgme.so.11 from system's standard library locations"
console.debug: "gpgme version: 1.16.0"
JavaScript error: undefined, line 0: Error: An unexpected error occurred
2024-05-09 06:02:19.324760505 UTC: sequoia-octopus: RnpKey::find_cert: No certificate in key store has the key D21C055EE2330F4ED30DCC156BB0B3C83F04FA06
But that key is in the keyring, as can be seen in this screenshot:
Other e-mails encrypted to the same key can be decrypted. Which information would you need to understand this better?