These settings work fine with Ipad and Imac, but they do not work on a Blackberry Bold or a Blackberry Classic. I phoned BT support, and they told me that I should speak to Blackberry support. Blackberry support did their best to help me, but they couldn't sync the calendar either.
Blackberry support contacted BT for me. BT told them that they do not support Blackberry.
Can this really be BT's best answer?
Is it really the case that caldav (an internet standard) is implemented by BT in a manner which works on IoS but not on Blackberry?