There is one contact for whom I always fail to decrypt their emails (using gpgol).
So I downloaded the encryptedPart separately (using webmail), and try to decrypt the file. This also failed.
I then turned on debugging in gpgme (level 9), and found that although the decryption claimed to fail, I could read the entire contents of the file in the debug file. ie it had de-crypted, but erroneously said that it could not.
I am reluctant to send you the file, or the debug output without some form of redaction. Is there anything obvious I can send you that would assist? I don't know if it is relevant, but the PGP version of the file is BCPG v1.54