WhatsApp for Infinix Hot 40i

XOS aggressively kills background apps to save battery, which holds back alerts until you reopen the app. Go to Settings > Apps > App management > WhatsApp > Battery usage and set it to "No restrictions." Then open Phone Master (or Settings > Battery), find the auto-launch / app-launch manager, and lock WhatsApp so it can run in the background. Finally, disable any global power-saving/battery-saver mode, since that re-throttles apps even after you whitelist them. See how others solved this on Reddit

First confirm notifications are allowed: Settings > Apps > App management > WhatsApp > Notifications, with the Messages channel set to make sound and show a banner/pop-up. The bigger cause on XOS is power management, so set WhatsApp's battery usage to "No restrictions" and lock it in the app-launch manager so XOS stops killing it. Also check the chat isn't muted and that Do Not Disturb (Settings > Sound & vibration) isn't silently filtering it. See how others solved this on Reddit

Most ads come from preinstalled XOS apps like Palmstore, Phone Master, and the file/cleaner apps. Open each one, look in its in-app Settings for "Recommendations" or "Content/news push" and turn those off. Then go to Settings > Apps > App management, open each offending app, tap Notifications, and disable notifications entirely. To cut targeted ads, go to Settings > Google > Ads and turn on "Delete advertising ID" (or opt out of ad personalization). See how others solved this on Reddit

Long-press the Palmstore icon, tap App info, open Notifications and toggle them all off, then set its battery usage to "No restrictions" reversed — actually restrict it so it can't run in the background and push ads. If you don't use it, disable or uninstall it via Settings > Apps > App management > Palmstore. For ads on the lock screen, open the wallpaper/magazine setting (Settings > Wallpaper & style, or the lock screen settings) and turn off any "magazine" or news/sponsored feed. See how others solved this on Reddit

Start by rebooting to clear stale system state, then clear the cache of any glitchy app via Settings > Apps > App management > (app) > Storage > Clear cache. Recheck Settings > System > System update, since early XOS builds often get quick follow-up patches. If problems persist, back up your data and do Settings > System > Reset options > Erase all data (factory reset) to clear leftover update conflicts. See how others solved this on Reddit

Sudden slowdowns are usually a misbehaving background app or full storage. Check Settings > Storage and free up space, then restart in Safe mode (press and hold the power button, then long-press "Power off" and confirm) to see if a third-party app is the cause. If it runs smoothly in Safe mode, uninstall recently added apps one at a time. Otherwise clear caches of heavy apps; as a last resort, back up and factory reset via Settings > System > Reset options. See how others solved this on Reddit