Mobile phone text messages are not read or deleted, and delivery is not displayed.

Does the subject want to ask, "Why don't you show delivery when the message is unread and deleted?" ? The mobile phone has no receipt report, so it is impossible to see whether the short message was sent successfully. When "Delivery Report" is not turned on in SMS settings, there is no receipt information. When the delivery report is opened, the delivery status depends on the value returned by the carrier network. Because different operators will lose the return value across the network, it is normal that the information is sent successfully, but the delivery report status is still to be sent.