Turn off the mute switch and silent mode.
Checking if this mute switch is switched off should be your first go-to step. You can find this tiny mute switch located above your Volume Up and Down buttons. Hence, it shouldn’t be a surprise that many users facing this “WhatsApp not ringing” overlook this minuscule switch. If the mute switch and Silent Mode is turned on, your ringtones and alerts will be silenced, and your phone only vibrates for incoming calls.
Ensure Do Not Disturb is Turned Off
Check the WhatsApp Notification Settings
In most cases, the main reason for WhatsApp calls not ringing is the app’s notification settings being set incorrectly. Thus, the restrictive settings might not allow call notifications or alerts when your phone is locked. Moreover, after a WhatsApp update, these settings may have been altered.
Hence, just to be safe, we recommend checking and enabling all the WhatsApp notification settings to see if that makes a difference.
For iPhone: From the Settings app, scroll all the way down, then select WhatsApp and tap Notifications.

Here, we suggest switching Allow Notifications off, and waiting about a minute, then turning it back on.

Next, under Alerts, tick all the alert options (i.e., Lock Screen, Notification Centre, Banners). Also, ensure that Sounds and Badges are turned on, and Show Previews is set to Always.

Hope this helps! :)