Summary

When dragging and dropping a Jira Issue Dates event within Team Calendar 5.5.0, the following message displays and the event can't be moved:
"An error occurred while trying to load the event.".

This should functionality should work as documented in Add Jira Events.

Environment

Confluence 6.2.2
Team Calendar 5.5.0

Steps to Reproduce

1. Create an issue in Jira with a due date of 1/21/18.
2. Create a Team Calendar and add an event by selectubg Jira Issue Dates and a Jira project. The event displays on 1/21/18.
3. Drag and drop the Jira event from 1/21/18 to 1/23/18.

Expected Results

Team Calendar should allow you to drag and drop the event to a different day and update the due date of the issue within Jira.

Actual Results

As a result of step #3 above, the following error is displayed in the UI:
"An error occurred while trying to load the event.".

In the logs, the following errors appear:

2018-01-19 10:31:02,755 WARN [http-nio-9622-exec-6] [extra.calendar3.util.TimeZoneUtil] tryParseDateTimeStringForEventEdit Unable to parse date 
 -- referer: http://localhost:9622/conf/calendar/mycalendar.action | url: /conf/rest/calendar-services/1.0/calendar/events.json | traceId: 7655efaed432da48 | userName: charlie
2018-01-19 10:31:02,783 WARN [http-nio-9622-exec-6] [confluence.impl.hibernate.ConfluenceHibernateTransactionManager] doRollback Performing rollback. Transactions:
  ->[PluginReadWriteTx]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT (Session #1905376747)
 -- referer: http://localhost:9622/conf/calendar/mycalendar.action | url: /conf/rest/calendar-services/1.0/calendar/events.json | traceId: 7655efaed432da48 | userName: charlie

It appears that the "Unable to parse date" message is innocuous as it will still appear if you use an older version of Team Calendars.

Workaround

Uninstall Team Calendar version 5.5.0 and install version 5.3.20.