See the following thread on Mozilla forum for logs: https://bugzilla.mozilla.org/show_bug.cgi?id=1268118

This is happening with Thunderbird 45.0 and Lightning 4.7.

The problem is for the creation of a new Event in Lightning, and also when trying to accept a new invitation. Nothing happens, the event is not created (or not accepted and remain in the queue list). Lightning log an error saying the creation of the event is refused serverside.

Steps:

- Create a new Event by double-clicking on a day in the calendar in Month view or using the Events & Tasks / New Event menu
- the New Event dialog pops up OK and I can fill all the information
- The dialog closes like normal when I hit Save & Close
- Then the Event is just not created, and wouldn't appear later (so not a slow synch)
- I am not using other extensions in Thunderbird, only Lightning
The calendar remain Synch for other/existing entries though into Lightning. And an Event created directly in Zoho calendar would show and can even be modified ok in Lightning.