WhatsApp for Honor 90 Lite

Magic OS aggressively freezes background apps, which stops the incoming-call screen from waking your display. Go to Settings > Apps > Apps, tap WhatsApp > App launch, turn off "Manage automatically," then enable Auto-launch, Secondary launch and Run in background. Next, open Settings > Notifications > WhatsApp and turn on Lock screen notifications, and check Settings > Apps > Apps > WhatsApp > More settings (or Permissions) to confirm "Display over other apps" is allowed so the full-screen call UI can appear. See how others solved this on Reddit

This is almost always Magic OS battery management killing WhatsApp while the screen is off. Go to Settings > Apps > Apps > WhatsApp > App launch, turn off "Manage automatically" and enable all three options (Auto-launch, Secondary launch, Run in background). Then in Settings > Battery, set WhatsApp to not be optimised/restricted. Inside WhatsApp, open Settings > Notifications and confirm Call notifications are on with a ringtone and vibration selected. See how others solved this on Reddit

Honor's power saving stops the app syncing in the background, so messages only land when you reopen WhatsApp. In Settings > Apps > Apps > WhatsApp > App launch, switch to manual management with all three toggles on, then in Settings > Battery remove any optimisation/restriction for WhatsApp and turn off Power saving mode while you test. Lock WhatsApp in the Recent apps screen so it isn't cleared, update it from the Play Store, and ensure Settings > Notifications > WhatsApp has all categories enabled. See how others solved this on Reddit

After enabling auto-launch and removing battery optimisation, the usual remaining culprit is the "Manage automatically" setting under App launch silently re-freezing WhatsApp. Set WhatsApp to manual launch control with all three options on, lock it in the Recent apps screen, and make sure adaptive/aggressive battery features are off in Settings > Battery. Also remove any third-party cleaner apps that auto-kill background processes, and keep WhatsApp updated. See how others solved this on Reddit

This is usually a missing storage permission, a corrupted cache, or a file exceeding WhatsApp's size limit. Go to Settings > Apps > Apps > WhatsApp > Permissions and grant Files/Storage (and Camera) access, then clear the cache via Settings > Apps > Apps > WhatsApp > Storage > Clear cache. If only large clips fail, trim the video or send it as a document, and confirm you are on the latest WhatsApp build from the Play Store. See how others solved this on Reddit