Unable to upload large file around 70MB on server

Everything works fine on local, but when I tried to upload a file to the server, it takes some time and shows the following error:

This site can’t be reached The connection was reset. Try:

Checking the connection Checking the proxy and the firewall Running Windows Network Diagnostics ERR_CONNECTION_RESET

Currently, my code looks like:

    $extension = $request->file('import_file')->getClientOriginalExtension(); // getting excel extension
    $dir = 'assets/files/contribution_data/';
    $filename = uniqid().'_'.time().'_'.date('Ymd').'.'.$extension;
    $request->file('import_file')->move($dir, $filename);

What might I be doing wrong here? How can I get rid of this problem?