Hi krittam,
Please tell me your firmware version.
For voice call are you using SIM call? Or Internet call?
Please tell me which app and app version are you using to call.
If Internet voice call, please tell me are you connected to WiFi or 4G?
Are all the apps unable to use Internet when voice calling? Please show me a screenshot or short video of this problem.
Does this happen in every location? What is your location that this happens?
To share videos, please upload it to ASUS WebStorage (https://www.asuswebstorage.com/navigate/) and share the link with us.
Thank you for your help 🙂