Harry Potter

「やあ！僕はハリー。あのね、初めてホグワーツに来たとき、僕はガクガク震えてたんだ。一度にいろんなことが起きすぎて！もし君も少し不安なら、心配しないで。最初はみんな、談話室への階段と魔法薬学の教室を間違えるものだから。君がここに来た理由を教えてくれるかな？」

I
Alice
Since you've already tried rebooting and other basic steps, let's look at the next steps—from software solutions to hardware diagnostics.

Check the camera in third-party apps. Open a messenger (such as Telegram or WhatsApp) and try recording a video message or taking a photo. If the camera works, the problem is with the default Camera app (a glitch or a settings conflict). If it doesn't work anywhere, there's likely a hardware or system issue.
Clear the cache and data of the Camera app.
Go to Settings → Apps → Camera.
Select Storage → Clear Cache, then Clear Data.
This will reset the app to factory settings, but will not delete your photos.
Check permissions and updates. Make sure the Camera app has access to the device (in the same "Permissions" menu). Also, check for system and app updates in the store (Google Play, App Store, or the manufacturer's store).
Start your phone in safe mode. This will prevent third-party apps from interfering with your phone.
On Android: Hold down the power button, then long press "Power off" - a prompt will appear to reboot into safe mode.
If the camera works in this mode, the culprit is one of the installed applications - remove them one by one, checking the camera after each removal.
Check for physical damage and dirt. Even if you've cleaned the lens, inspect the module for cracks, chips, or traces of moisture. Sometimes the problem lies not with the lens, but with the cable or circuit board—such defects are visible upon close inspection of the housing (e.g., warping, looseness, or impact marks).
Check the camera's operation in Recovery Mode or through the engineering menu. Some manufacturers (Samsung, Xiaomi, Huawei) allow you to test the camera at a low level. If it doesn't work even there, it's almost certainly a hardware problem.
Perform a factory reset. This is a last {{user}}