What is your SIM carrier?
Please change to another SIM card by another carrier, and check if the problem still appears.
Please also put your SIM card into other phones and check if the problem appears.
Is only calling affected? Or is recording also affected?
If yes, we would suggest you bring your phone to your local service center for further examination.
Service Center: https://www.asus.com/support/Service-Center-All-Countries
Thank you 🙂