Why is it black or blue bubbles?

Because iMessage is hacked, blue bubbles will appear when you come in. This is because the blue bubble indicates that the message was successfully sent, while the gray bubble indicates that the message was not successfully sent. Although hacked, the message has been successfully sent to the other party's equipment, but the other party has not received the notice, so it is impossible to know whether the other party has seen the message. It should be noted that if you are blacked out by the other party, you will not be able to see the "read" or "entering" status of the other party, and you will not be able to communicate with the other party in an ordinary way.