First thing, there is no such thing as “login with base URL” anymore.
Second thing, I’ve been lazy for months to report this but finally registered on the forums just for that:
https://yandex.ru works as expected here:
This is because they have SRV records for CalDAV and CardDAV:
~> host -t SRV _caldavs._tcp.yandex.ru _caldavs._tcp.yandex.ru has SRV record 0 1 443 caldav.yandex.ru. ~> host -t SRV _carddavs._tcp.yandex.ru _carddavs._tcp.yandex.ru has SRV record 0 1 443 carddav.yandex.ru.
If this does not work, maybe there’s something wrong with your DNS resolver.