macOS High Sierra 10.13.3 update is stuck at downloading

I have a Macbook Pro 2017 13-inch with touch bar and its macOS version is 10.3.1, when I started downloading macOS 10.3.13 on App Store, everything seemed fine until when 5 mins later I looked at it again, it was not downloading, everything was the same as it hasn't started. I observed the download and found that at around the point where 300 mb downloaded, the download seems to slowdown and stopped due to unknown reason and it became the same. I've been restarting the download for half a day now, nothing seems to be progressing.

Does anyone know what causes this issue?

Thank you.