Mac Calendar "Server responded with an error" message

Firstly, try updating your macOS to the latest version available. Software updates often include bug fixes and improvements that can address issues like these. Additionally, ensure that your Calendar app is also up to date by checking for any available updates in the App Store.

If the problem persists after updating your software, consider resetting the Calendar app. To do this, navigate to the "Calendar" menu in the top-left corner of your screen, then select "Quit Calendar." After quitting the app, reopen it and check if the error message still appears. Sometimes, simply restarting the app can resolve temporary glitches.

If resetting the app doesn't work, you may need to troubleshoot further by examining your internet connection and network settings. Poor internet connectivity or network issues can sometimes interfere with the Calendar app's ability to communicate with the server. Ensure that your internet connection is stable and that your network settings are properly configured.

If none of these steps resolve the issue, consider reaching out to Official Apple Support for personalized assistance. They can provide further guidance and troubleshoot the problem in more detail. Additionally, if you're planning to purchase a new Mac, it's worth noting that the issue may not necessarily carry over to the new device, especially if it's related to software or configuration settings specific to your current Mac.