Nokia Lumia 1020 white noise instead of sound when recording?

I bought a Nokia Lumia 1020 and I'm amazed with it so far. Personally I like it more than my old iPhone. But just a few moments ago I decided to record a video for the first time. The picture is really good, but instead of getting any recorded sound, there's like white noise instead of anything else.Am I doing something wrong?

Thanks

Added (1). The microphone is clean and everything. I think I might have gotten a faulty phone?

Clean the microphone maybe

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