Many iPhone users report that WhatsApp messages don’t arrive (or notifications don’t show) when their phone is locked (screen off). In some cases, the app will only sync new messages once you unlock the phone and open WhatsApp. This can happen even though notifications are supposed to work in the background.
Common symptoms include:
- No lock-screen alerts for new WhatsApp messages
- Messages not appearing until you unlock and open the app
- Delayed message delivery
- “Connecting…” status inside WhatsApp until the app is foregrounded