I am trying to connect to a hosted CalDAV account and running into a lot of issues, I am able to connect through my iPhone to the hosted calendar but when I try the same settings in Thunderbird it does not work, or say 'The ''hosted'' calendar is momentarily not available.' I've reached out to my host and they have given me the address that works with my iPhone, the only thing I think it could be now is a bug in Thunderbird...