Calendar “Subscription” Virus/Spam
Here’s my issue. It keeps popping up. I went to the accounts in my calendar settings and deleted the spam account but it keeps popping up. Never clicked “OK” on it.
Are you seeing something as shown in the pic below? This is neither a hack nor a virus. It is spam and you can get rid of it. Read 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.