Spam on calendar
I have strange messages on my calendar which I didn’t wrote on it. Strange reminders about the safety on my phone and it include some link that I don’t want to open.
iPhone 6s, iOS 14
Are you seeing something as shown in pic below?
Then probably you have accepted an offer or subscribed for a spam Calendar accidentally. Watch the GIF below to know how to unsubscribe from these alerts. Look for an unknown Calendar on the device under subscribed calendars.