Check the following:
- Check whether power-save mode is on.
If you do not operate the product for a certain period of time, the camera enters power-save mode.
Power-save is released by performing operations such as pressing the shutter button halfway.
You can change the length of time before the camera enters power-save mode. For details, refer to the operation manual.
- Check whether same thing happens with another battery pack.
If you have several battery packs, try another battery pack.
If the same thing does not happen with another battery pack, there may be a malfunction in the battery pack.
If the issue is still unresolved, the product may need to be repaired.