Apple devices synchronize calendar subscriptions with their iCloud service. Usually this works automatically and well.
Sometimes this synchronization fails. When you delete a subscription, this deletion is not sent to iCloud, so iCloud does not know about it. When the devices download the current status of iCloud calendars, the deleted calendar is still there, and it reappears.
Since the issue is with iCloud, it can't be fixed by WebCal.Guru. Please try the following in order.
Reboot the affected device.
To do this, hold the power button until you see a screen like the one on the right.
Slide the control to the right to turn off the device.
Then, turn to device back on.
Try to delete the calendar again. If the issue has not been fixed, please continue to the next step.
If rebooting did not fix the issue, next we'll try logging out of iCloud and then logging back in.
Open the Settings app.
Tap on your name at the top of the screen.
The Apple ID opens.
Scroll to the bottom of the screen.
If the Sign Out is not enabled, you need to turn Screen Time off. Tap Settings and go to the next step.
If the Sign Out is enabled, jump to Step 10.
Go back to the Settings app list.
Scroll to Screen Time and open it.
Tap Turn Off Screen Time.
Tap Turn Off Screen Time.
Once Screen Time is turned off, you can log out of iCloud.
Go back to the iCloud setting screen by clicking Settings and selecting your name at the top.
On the iCloud screen, tap Sign Out.
If you have a different account for iCloud and Store, it is enough to Sign Out if iCloud.
Enter your Apple ID password.
Since you'll be logging right back in, you do not need to keep a copy of data on the device.
It takes a while to log out.
Now you've logged out of iCloud.
To log back in, tap on iCloud and proceed.
Then try to delete the calendar again.
Updated Wed, 08 Feb 2023 12:08:23 +0000 UTC