Ros basic final exam -- simulation not loading ---Urgent

I am sorry to inform you that I am trying to solve the final exam of Ros basic path. I am actually facing difficulties. My simulation is loading continuously while other contents are working perfectly. So, I am now unable to check the simulation for my code. The final exam time is limited to 4 hours. I was hoping to get an certificate for this path. But now, It seems I am unable to get the certificate without trying to solve. I am hoping for some suggestions from the authority like what should I do? I have a problem like this:

Hi @marzanalam3,

I’m sorry about this problem but, first, let me assure you that you will be able to attempt this exam as many times as you want. Forget the 4 hours bit.

Now to the problem. I just checked here and found that the simulation is loading fine here, so there might be some problem on your side preventing it. Please try the following, in order:

  1. Try again. It might just work this time.
  2. Are you using a browser other than Chrome or Firefox? Switch to any of these two.
  3. Are you working in incognito or private mode? Please switch to normal mode.
  4. Try clearing your browser cache.

Please let me know if any and which of these works for you.

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