I am using Siskin version 6.4 on iOS 14.6. The account on Siskin is trying to send and receive messages with Omemo encryption with another account using Profanity version 0.11.0.

The account on Profanity can send encrypted messages to the user on Siskin with no issues.

Unfortunately, the account on Siskin cannot send messages with Omemo encryption to the user on Profanity. Siskin reports that "There is no trusted device to send message to" even though the Profanity user has trusted the Siskin user's Omemo fingerprint. Within Siskin, if I go to the Profanity contact's details, "Message Encryption" is set to "OMEMO" and the key is selected. The key matches the Profanity fingerprint.

Each user is also in the other's contact list/roster. Each is also subscribed to the other's presence.

Any suggestions on what to try to resolve this?