All of a sudden all my event are disappeared?

Sometimes some devices have a problem with syncing with iCloud and it makes your all data looks like disappearing all of sudden. 
In this case, you can reset your network settings to fix the issue. Please try the steps below.
  1.  Delete one of the accounts.
Settings > Mail, Contacts, Calendars > iCloud, Exchange, .... account > Delete Account
  2. Reset Network Settings
Settings > General > Reset > Reset Network Settings
The phone will reboot.
  3. After the phone reboots
Don't add any WiFi networks, until after you set up your account again
Set up your iCloud, Exchange, .... account again
Settings > Mail, Contacts, Calendars > Add Account
Fill in all your settings
After that, your account should sync up.
  4. Once you've verified that the account is working, then you can add your WiFi network back in, and it should keep working.
If the problem persists, please contact to Apple technical support since Awesome calendar is using Apple calendar database.

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