Hi chiang272,
Thank you for using Apple Support Communities. It sounds like you are having issues with your AirPods while using WhatsApp and WeChat, and we'd like to help.
Is this just happening with the microphone, or can you not hear as well? Does this happen with regular calls or FaceTime?
If this is just happening with these two apps, please follow the steps here, even though you are experiencing different symptoms: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support
For more system-wide issues with your AirPods, check out this resource: How to reset your AirPods and AirPods Pro - Apple Support
Let us know the results.
Cheers.