WhatsApp for Samsung Galaxy Y Plus S5303

This is almost always battery optimization killing WhatsApp in the background. Go to Settings > Apps > WhatsApp > Battery and set it to Unrestricted. On older Galaxy firmware look under Settings > Application Manager > WhatsApp and disable any power-saving restriction. Also turn off Settings > Device care > Battery > Background usage limits, or add WhatsApp to the never-sleeping apps list so it stays connected. See how others solved this on Reddit

WhatsApp's notification channel has likely been set to silent. Open Settings > Apps > WhatsApp > Notifications, tap the Messages category, set Importance to 'Make sound and pop on screen' (High), and re-select a notification tone. Then inside WhatsApp go to Settings > Notifications and confirm the conversation tone and vibration are both turned back on. See how others solved this on Reddit

App updates sometimes reset notification channels, so re-check them in Settings > Apps > WhatsApp > Notifications and re-enable the Messages and Group categories with High importance. If they look correct but still misbehave, clear the cache via Settings > Apps > WhatsApp > Storage > Clear cache (not Clear data), then force stop and reopen the app. Updating WhatsApp itself in the Play Store usually restores the expected behavior. See how others solved this on Reddit

Samsung's aggressive memory management pauses apps it thinks are unused. Open Settings > Device care > Battery > Background usage limits, disable 'Put unused apps to sleep' and 'Auto-disable unused apps', and remove WhatsApp from the Sleeping and Deep sleeping app lists. Keeping WhatsApp updated and excluded from these limits stops Samsung from repeatedly suspending it. See how others solved this on Reddit

Watch notifications only mirror what the phone shows, so first make sure WhatsApp notifications appear on the phone itself, then open the Galaxy Wearable app > Notifications and confirm WhatsApp is toggled on. Turn off 'Notifications while phone in use' so alerts still reach the watch when you're holding the phone, and avoid swiping away phone notifications before the watch syncs them. Re-pairing the watch or toggling WhatsApp off and on in the Wearable app clears most stuck states. See how others solved this on Reddit

Duplicate alerts happen when both the phone and the watch are surfacing the same WhatsApp notification. In Galaxy Wearable > Notifications, review the 'Show notifications individually' option and make sure WhatsApp isn't enabled twice across different categories. If they keep stacking, clear the cache for both WhatsApp and the Galaxy Wearable app under Settings > Apps, then restart both devices. See how others solved this on Reddit