I know this question repeated many times but I really have a strange situation, I installed Odoo-Nightly (also tried odoo-Github) on a production server many times but WKHTMLTOPDF didn't render the header and footer for reports, I installed the same ISO of Ubuntu 14 server with same steps of installing odoo on a VMWARE for both Odoo-Github and Odoo-Nightly, reports printed well, I tried to reinstall a fresh copy of Ubuntu on the production  server but reports in pdf still not printing the header and the footer (only printing them in Html).

Any one has an idea about the previous issue?