When I try to open an encrypted message, Gnus asks me for my passphrase, which it seems to accept. But then it doesn't decrypt the message, and it doesn't report errors either.
I can otherwise decrypt the message by directly feeding its text to GPG. How do I debug this problem?
More info: If I run M-x
epa-decrypt-region on the text of the message, while in Gnus, it decrypts it.
The key associated with the sender has multiple email addresses associated with it, and the address in question is the second in the list. Is it possible that this is a problem?