I am running in to a strange issue. On my local computer my export to excel/word/pdf script is running perfectly fine. But as soon as I run the script from live server, it creates a 0 byte file. Unfortunately, it doesn't even trigger any error. It silently opens the download dialog and result in either a 0 byte OR in a best shot couple of rows.
memory_limit, max_upload_size etc are cross matched local server and everything is perfectly fine.
Just in case somebody is looking for the answer. Look for PHP fatal errors. This halts the export process and it will result in empty file. Its difficult to look for these errors as window exporting to excel closes automatically.