How to Fix the “Server Responded with an Error” Message in Mac Calendar

Not long ago, I opened the Calendar app on my iMac and was hit with an annoying message: “The server responded with an error.” (see the screenshot below)

The alert gave me three choices—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 seeing this error too, you’re not alone—and the good news is that I found a few things that worked.

In most cases, 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.

We covered a similar issue in 2021, this article reflects the most recent macOS changes.

Turn Google Calendar Off and Back On

This was the fix that did the trick:

1. Go to System Preferences or Settings > Internet Accounts.
2. Select your Google account from the list on the left.
3. Uncheck the box next to Calendars to temporarily disable calendar syncing.
4. Restart your Mac.
5. Wait about 10 seconds.
6. 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 solve it—or if the issue comes back—you can try removing the Google account entirely and setting it up again:

1. Open System Preferences or Settings > Internet Accounts.
2. Select your Google account, then click the minus (–) button to remove it.
3. Restart your Mac.
4. Go back to Internet Accounts and click the plus (+) button to re-add your Google account.
5. Make sure Calendars is checked during setup.

See this article for more details: How to Add or Delete Calendars on Mac

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 you’re on 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 persists.

See also:

• How To Stop iCloud Calendar Spam
• iPhone or iPad Calendar Search Not Working, How to Fix