My elderly father in Italy is using a CMF Phone 2 Pro running:
Galaga-B4.1-260812-17290eea
Since recent Nothing OS / Android updates, WhatsApp has become effectively unusable on Wi-Fi.
Symptoms
WhatsApp loses internet connectivity when connected to any Wi-Fi network
Messages do not send or arrive
WhatsApp calls do not work
Other apps appear to have normal internet connectivity
As soon as Wi-Fi is disabled and the phone switches to 4G/mobile data, WhatsApp immediately works again
The issue occurs on multiple completely different Wi-Fi networks, so it is not router-specific
Uninstalling and reinstalling WhatsApp temporarily fixes the problem, but after some time the issue returns
Troubleshooting already attempted
Tested multiple Wi-Fi networks
Reset Wi-Fi / mobile / Bluetooth network settings many times
Reinstalled WhatsApp multiple times
WhatsApp proxy is disabled
Private DNS is disabled
No VPN is configured
Background data is enabled for WhatsApp
Unrestricted battery/background usage enabled
Adaptive Connectivity disabled
None of these changes resolve the issue.
The most distinctive behaviour is:
WhatsApp does not work over Wi-Fi, but immediately starts working when switching to mobile data.
Because reinstalling WhatsApp temporarily restores Wi-Fi connectivity before the problem eventually returns, this looks like a regression involving Nothing OS 4.1 / Android networking or per-app network state rather than a Wi-Fi/router configuration problem.
Additional finding: Installing Cloudflare 1.1.1.1 and enabling WARP completely resolves the problem while remaining connected to Wi-Fi. Disabling WARP causes WhatsApp connectivity to fail again. This strongly suggests a Nothing OS 4.1 Wi-Fi routing / IPv6 / DNS regression rather than a WhatsApp configuration issue.
