First off, when I try to export the file as csv, I only get the first sheet but not the others.
Second, when I try to export it as PDF, I get the following error:
Constant DOMPDF_ENABLE_AUTOLOAD already defined
I use the DOMPDF elsewhere on the site (not Laravel Excel, but DomPDF) and it works just fine...
Thirdly, when I try it on my server with ssl certificate, I get this error:
:#20 ErrorException: file_get_contents(): SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify faile`
Locally it works just fine...
To answer your first questions - a CSV file doesn't have sheets. It's a flat file with rows and columns.
Second - DOMPdf is loading earlier in your application and the constant can't be re-defined. You will have to not load it earlier, or comment out the code to reload the constants in the Excel library functions.