If all data is not synchronized

First, please check if your settings are correct.

Please refer to this page.

In addition, please check the following points

Are the calendars you have selected to sync with Shift Work Calendar set to be displayed in the Google Calendar application?
If you have multiple Google accounts, are you using the same account for both Google Calendar and Shift Work Calendar?
Does it not sync after restarting the app or device?

If this is correct but does not work, try the following

In Google Calendar, create a new calendar
Select that calendar as the calendar to sync from the settings screen of Shift Work Calendar
Exit the application (synchronization will be performed)

If some shift patterns do not sync

Please set a value higher than 0:01 as it will not be synchronized.

Data from all time periods will not be synchronized.

Data from 7 days prior to and 90 days after will be synchronized.