How to get rid of calendar pop-up "Your response to the invitation cannot be sent" in iphone 11?

Hey there mchujia,

It seems like you're having difficulty getting rid of a pop up about responding to a calendar invitation.

You've tried some great troubleshooting so far. The following article will walk you through some more helpful steps:

How to unsubscribe from calendars on your iPhone

Pay close attention to this section:

"Delete specific calendar invitations 

To delete an invitation that you already accepted, tap the event, then tap Decline or Delete Event. If you unintentionally subscribed to a calendar that you don’t want:

1. Open the Calendar app. Then tap Calendars and look for an unknown or suspicious calendar. 
2. Tap the calendar. 
3. Scroll down, then tap Delete Calendar."

If your iPhone is frozen on this pop up screen then try the steps in this article:

If your iPhone, iPad, or iPod touch won't turn on or is frozen

Hope this helps!