Newbie Lightning CalDAV Questions [SOLVED[

[llewellen]

[SOLVED] My ISP finally, reluctantly coughed up the info that they don't support CalDAV for personal, residential email accounts. I would have to pay extra for a business account to get that functionality. There is NO competition in my area so I'm stuck with them (and they know it as they chuckle).

Sorry if this has been asked and answered but I couldn't find it and I have spent 2 days trying.
Lightning 4.7.4 Thunderbird 45.3.0

My ISP provides webmail on a Zimbra platform. I have 4 accounts, each with calendar, that I want to sync on the desktop with Thunderbird Lightning. Webmail is already synced and running fine on my Blackberry.

When I click in Thunderbird on New Calendar, a dialogue box appears asking first for either local or network calendar. I click network. Next box asks for type of connect. I click CalDAV and there is a box asking for "Location". Please enter a valid location. Which "location"? Of what? My ISP has no clue and simply says that their webmail doesn't support exchange/active sync for Thunderbird (which I'm not trying to use anyway). End of online assistance. Zimbra instructions are no more illuminating.

BTW I can't use Zimbra Desktop because they don't have a 64bit version available yet.

Any help greatly appreciated.