verbose_ssl=yes would log more.
It didn't actually - just tried that, same result.
ssl_verify_client_cert: yes .. ssl_require_client_cert: yes
Did this really work with UW-IMAP or are you just now trying to set
this up? Are you sure iPhone is even supposed to work with this?
In my previous config I used certs only for sendmail relaying on the mobile thunderbird clients, and used SSL/passwords for imap. When I upgraded to dovecot, it started requiring the certs for access locally and remotely and I added the cert to the desktop and all was fine. I'm not 100% sure the iphone supports this - the docs are really murky but as of the last release, they rolled out enterprise support to keep the exchange users happy and it seems to support certificate installation, root certs, client certs etc. If it doesn't I'd just like a clean error message. The iphone says effectively ssl error, are you sure the server supports ssl? and your account settings are correct (sorry it's actually in german otherwise I'd quote it literally). Dovecot is just saying it's disconnecting. I had a very different error from dovecot when the thunderbird clients didn't have certificates, "Client didn't present valid SSL certificate"
Darren