Iphone 5s SMS always shows unread SMS. What should I do?

When the messages of iphone 5s always show unread messages, but we can't see them when we open them, we can try the following methods:

After restarting the phone, the phone will also display this message, just click in.

Under the mobile phone operation: Settings-Application Manager-Slide Screen Options (All)-Find Information-Click to enter to clear data.

Please back up telephone data (phone book, SMS, multimedia materials, etc.). ) and try to restore the phone to factory settings (Settings-Reset-Restore Factory Settings).

Note: all the data stored in the mobile phone is lost, so it must be backed up to the sim card and sd card in advance before operation.