Recently, I opened the Calendar app on my iMac and was hit with an annoying message: "The server responded with an error."
The alert presented me with three options–Revert to Server, Try Again, and Ignore–but none of them did anything. No matter what I clicked, the message wouldn’t go away, and the Calendar app froze completely. I had to force quit just to get control of my Mac again.
If you’re also getting this error, you’re not alone. Luckily, i found a solution.
In my experience, this error is tied to a calendar account that’s syncing with a third-party service–especially Google Calendar. Something gets out of sync or stuck behind the scenes, and the Calendar app can’t recover gracefully. Instead, it locks up and throws this error message.
Turn Google Calendar Off and Back On
This is the fix that worked for me:
- Go to System Preferences or Settings > Internet Accounts.
- Select your Google account from the list on the left.
- Uncheck the box next to Calendars to temporarily disable calendar syncing.
- Restart your Mac.
- Wait about 10 seconds.
- Check the Calendars box again to turn it back on.
That’s it. After doing this, I reopened the Calendar app–and the error was gone. My calendar events reappeared, and syncing resumed as expected.
Remove and Re-Add the Account (If the Error Returns)
If turning Calendar off and on doesn’t fix the problem-or if the issue comes back–you can try removing the Google account entirely and setting it up again:
- Open System Preferences or Settings > Internet Accounts.
- Select your Google account, then click the minus (–) button to remove it.
- Restart your Mac.
- Go back to Internet Accounts and click the plus ( ) button to re-add your Google account.
- Make sure Calendars is checked during setup.
This resets the sync connection from scratch and has worked for many people when toggling Calendar alone wasn’t enough.
Check for macOS Updates
Sometimes these types of bugs are fixed quietly in system updates. It’s worth making sure your Mac is running the latest version of macOS:
- Go to System Preferences or Settings > Software Update and install any available updates.
After updating, reopen Calendar and see if the error is gone.