Download file of demo didn’t work!

Hi everybody,
I’m really disappointed.
I added the ENFOLD theme successfully more than two weeks ago. I can not upload any demo though.

The message I get is Download file of demo “Construction” didn’t work! You might want to reload the page and try again.

I read so many articles, I read that maybe trying to upload the demo manually might work. I did that, nothing changed.
I’m reading about the time expiration? I don’t know what to do about that, and I don’t understand the answers people are getting about this. I have no technical or coding knowledge.
I also contacted the hosting company and they said they are not seeing an issue on their end. I read about that as well, that maybe something is blocking the IP or something.

So, I purchased this theme believing that I would be able to modify a demo and make the process simpler for me, since this is my first try.

I have a friend who is a coder, he suggested this theme to me. He is using this theme all the time and never had any issues like this. He doesn’t know how to help me.
So, now it is useless to me, and I feel helpless.

IF you can help me, PLEASE DO and try to explain with simple instructions.

Thank you very much in advance.