Where is the SMS inbox of Nokia 5330? Why did the received message disappear after reading it?

Did you change the location of the email after reading it?

Suppose your original information is stored in the memory of your mobile phone. When you change the storage location to a memory card, the original message will not be visible, but when you change it back to the storage location, you can see the original message again. Short messages are often deleted, which takes up memory.

Or you can change the default storage quantity of information to be slightly larger, from the default 100 to 300.

Do not rule out the system fault, go to brush the machine.