Laravel 5 drops "This site can’t be reached" when trying to download file

I have Laravel 5.2 and PHP7.

My host works as it should, except links that generate and download xlsx files using PHPExcel. These links drop error "This site can’t be reached". All libraries within a project are installed (and I assume that if problem was in libraries, I would get 500s about missing classes or something like that).

Maybe some php extension is missing? What am I doing wrong?

via Chebli Mohamed