Why does the iPhone's calendar receive spam advertisements? How to ban it

The information received by IOS and MacOS devices is pushed by Apple iMessage. They were originally used to add friends to keep in touch with each other, but for some reason, they were used by criminals. They can fill in the text at the account invitation and push advertisements to the AppleID of ordinary users. If users synchronize the iPhone system calendar with the iCloud calendar, they may receive a prompt in the iPhone and display the spam preset by criminals, and the same message prompt information will appear in the networked iOS or Mac OS devices such as iPad or MacBook logged in with the same account. In the latest version of Tencent Mobile Manager, calendar advertisements have been cleaned up. You can swipe up to advanced features in the phone manager, and then select "calendar advertisement cleaning" to clean up.