WhatsApp for Nord N100

OxygenOS aggressively closes background apps to save battery, which silences WhatsApp until you open it. Go to Settings > Battery > tap WhatsApp (or Settings > Apps > WhatsApp > Battery) and set it to 'Don't optimize' / 'Allow background activity'. Then open Settings > Apps > WhatsApp > Notifications and confirm notifications are enabled. Finally, open the Recent Apps screen and lock WhatsApp so the system stops clearing it from memory. See how others solved this on Reddit

This is usually a corrupted cache or an outdated app version conflicting with the system update. Open Settings > Apps > WhatsApp > Storage usage and tap Clear cache (not Clear data, which would delete chats), then update WhatsApp from the Play Store. If it still misbehaves, restart the phone and confirm OxygenOS itself is fully updated under Settings > System > System updates. See how others solved this on Reddit

This is typically a proximity-sensor issue: the phone thinks it's held to your ear and keeps the screen off. Clean the top of the screen near the earpiece, where the sensor sits, and remove any thick screen protector covering it. Make sure WhatsApp has the Phone/Calls and Microphone permissions under Settings > Apps > WhatsApp > Permissions so call screens load correctly, then restart the phone. If it persists after an update, clear the WhatsApp cache via Settings > Apps > WhatsApp > Storage usage. See how others solved this on Reddit

WhatsApp can't sync without a working data connection, and the N100 sometimes drops Wi-Fi or mobile data after a reboot. For Wi-Fi, go to Settings > Wi-Fi, tap your network and choose Forget, then reconnect with the password. If it keeps failing on either Wi-Fi or mobile data, open Settings > System > Reset options > Reset Wi-Fi, mobile & Bluetooth. Once you're back online, reopen WhatsApp and pending messages and media will go through automatically. See how others solved this on Reddit

Restore only works when the backup, phone number, and Google account all match exactly. Make sure you're signed into the same Google account (Settings > Accounts) that holds the backup, then reinstall WhatsApp and verify the same number so the restore prompt appears from Google Drive. If the error continues, confirm WhatsApp has Storage/Files and Contacts permissions under Settings > Apps > WhatsApp > Permissions, and check that a recent backup exists in WhatsApp > Settings > Chats > Chat backup. See how others solved this on Reddit

The N100 is a budget device that received limited OxygenOS updates, so over time you may notice more background-app and notification quirks than on flagship OnePlus phones. To keep WhatsApp stable long-term, install the latest system update under Settings > System > System updates, keep WhatsApp current in the Play Store, and periodically clear its cache via Settings > Apps > WhatsApp > Storage usage. With those habits the phone handles WhatsApp fine for everyday messaging despite its age. See how others solved this on Reddit