Shared Calendar Not Syncing

Hi Epic-Ian,

Thank you for participating in the Apple Support Communities. We understand you're having trouble syncing a shared calendar. This article has some relevant steps that may help: If your iCloud Contacts, Calendars, or Reminders won’t sync.

"Things to check first

1. Check the system status of iCloud Contacts, Calendars, or Reminders for services outages or connection issues.
2. If a reminder isn't showing up on some of your devices, make sure that your iPhone and iPad have the latest version of iOS or iPadOS, or that your Mac has the latest version of macOS.
3. Make sure that you're signed in to iCloud with the same Apple ID on all of your devices. Then, check that you turned on Contacts, Calendars, and Reminders in your iCloud settings.
4. Check that the date and time settings on your device are correct for your current location. 

iOS and iPadOS

After each step, check your contacts, calendars, or reminders. 

Restart the Contacts, Calendar, or Reminders app

1. Close the app.
2. Return to your Home Screen.
3. Wait about one minute, then open the app again.

Refresh your contacts and calendars

To refresh your contacts, open the Contacts app and swipe down on the list. To refresh your contact groups, tap Lists in the upper-left corner, then swipe down on the list. 

To refresh your calendars:

1. Open the Calendar app.
2. Tap the Calendars tab.
3. Swipe down on the list to refresh your events.

Check your app settings

If you use multiple groups or accounts in the Contacts or Calendars app, make sure that your iCloud Contacts and Calendars are set to appear:

• Open the Contacts app and tap Lists in the upper-left corner. Make sure that All iCloud is selected.
• Open the Calendar app and tap the Calendars tab. Make sure that all iCloud calendars are selected. 

Change how often your calendars update: 

1. Tap Settings, then tap Calendar.
2. Tap Sync.
3. If All Events is selected, choose a specific timeframe instead, like Events 1 Month Back. If a specific timeframe is selected, choose All Events instead. 
4. Return to your Home Screen. 
5. Wait a few minutes, then open the Calendar app. Tap the Calendars tab, and swipe down to refresh.

Since the iCloud Birthdays calendar updates daily, changes to birthdays might not appear in the Calendars app until the next day.

Set iCloud Contacts, Calendars, or Reminders as your default

If your contacts, calendars, and reminders are in iCloud, then iCloud automatically updates your information. If your information is in a third-party account, like Google or Yahoo, you can change your default account to iCloud. Changing your default account to iCloud won't move your existing information from a third-party service to iCloud.

Calendars and Reminders

To check which account your calendars are in, open the Calendar app, then tap the Calendars tab. 

Set an iCloud calendar as the default calendar:

1. Tap Settings, then Calendar.
2. Tap Default Calendar. 
3. Tap a calendar under iCloud to make it your default.

Restart your iPhone, iPad, or iPod touch

• Learn how to restart your iPhone.
• Learn how to restart your iPad.
• Learn how to restart your iPod touch."

If the issue persists, Contact Apple Support for further assistance.

Take care.