Subscription expired:

This may be caused by your admin removing your membership or updating your access groups.

To fix this issue:

• Remove your existing subscription.  Via settings / calendars / accounts on an iPhone or calendar settings on Android.
• Re-sync your team's calendar by going to the events or schedules list and hitting the 'subscribe' link.

Note: If the admin has removed your access or your membership you may need to request access first.