If you do not use the camera for a long time, the built-in battery that maintains the time and date may be discharged. To recharge the built-in battery, place a charged battery pack in the camera and leave the power turned off for more than 24 hours.
NOTE: The date and time can be reset after the built-in battery has been recharged.
If the issue is still unresolved, service may be required. Begin the procedure to send your Sony product into a Sony facility to be repaired.