What app not working

[mani_mozhi]

Asus ZenFone Shellie zd551'll model whatsapp not working and 4g calls not supported
Jio4g not support

[Christine_ASUS]

Hi mani mozhi
Thank you for your asking. Kindly provide the information below so that we can better assist you.
1. Your current firmware version
Settings>System>About Phone>Software information
If you try to update to the latest version, does the issue still persist?
2. Does the issue appear right after any system/apps' download or update?
3. Can you use 4G before with this model in your area?
4. Can you use Whatsapp before? As I saw you are in certification page, what do you mean that you can not use Whatsapp?