Mac Calendar authentication rejected by BaiKal?

A couple of months ago, I set up the Baikal calendar and contacts sharing app on my OS 6.8.8, RND314, and it worked perfectly from several different Macs (OS 10.6 & OS 10.8) and an iPhone (iOS 7.0.4). After several small system updates on the Macs and iPhone, I now get authentication errors. I've carefully copied and pasted the same passwords into the Baikal admin UI, and into the Apple Calendar apps, but now I get the same "your username and password were rejected by the server". Has anybody else seen this?