Hello all.It looks like that relatively fresh Thunderbird fails to establish second TLS connection to server if TLS session caching is enabled at server side. E.g, it fails to open Sent folder while Inbox is opened. Diagnostc in server logs is dumb: "imaps TLS negotiation failed".Setting "tls_session_timeout: 0" solves the problem. "A value of 0 will disable session caching".As far as I see, Thunderbird 91 is not affected, 115 is affected. Cyrus IMAP 3.6.1 in Debian Stable.
I'm using Thunderbird 115 and Cyrus 3.4 without any problems.
Perhaps try and delete your tls_sessions.db file (after stopping cyrus master) and then restart it. It should get re-created on startup.
Mark
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