This might be related to the paperformat?

You will find some ideas to solve your problem here: https://www.odoo.com/forum/help-1/question/custom-header-div-class-header-overlaps-with-report-body-div-class-page-in-custom-sales-order-report-91294

hi, 

hear the problem was installation of wkhtmltopdf 

i have same issue in odoo 16 finally i corrected by proper installation of wkhtmltopdf

first we have to install wkhtmltopdf ubuntu 22 terminal

      1.    apt install wkhtmltopdf

      2. wkhtmltopdf --version 

      whether its 0.12.6 remove and download 0.12.5

      3.wget https://github\\\.com/wkhtmltopdf/wkhtmltopdf/releases/download/0\\\.12\\\.5/wkhtmltox_0\\\.12\\\.5\\\-1\\\.bionic_amd64\\\.deb

     \\\ 4\\\.sudo\\\ dpkg\\\ \\\-i\\\ \\\ wkhtmltox_0\\\.12\\\.5\\\-1\\\.bionic_amd64\\\.deb

sometimes\\\ it\\\ may\\\ error\\\ then\\\ try\\\ to\\\ install\\\ one\\\ or\\\ two\\\ things 

    \\\ 1\\\.wget\\\ http://archive\\\.ubuntu\\\.com/ubuntu/pool/main/o/openssl/libssl1\\\.1_1\\\.1\\\.1\\\-1ubuntu2\\\.1\\\~18\\\.04\\\.22_amd64\\\.deb

   \\\ 2\\\.sudo\\\ dpkg\\\ \\\-i\\\ libssl1.1_1.1.1-1ubuntu2.1~18.04.22_amd64.deb

    3.sudo apt-get install xfonts-75dpi

    4.sudo apt-get update

    5.apt --fix-broken install

finally confirm  the "wkhtmltopdf version is  0.12.5"

Ive the same issue using odoo ce 10 
working in windows server 
any help plz 

Hi, I went inside the code and I found that :
1) I found where  is called and header and footer and called through parameters --header-html and --footer-html

2) I got a warning message in odoo.log (_logger.warning('wkhtmltopdf: %s' % err) in the python source) :

The switch --header-spacing, is not support using unpatched qt, and will be ignored.The switch --header-html, is not support using unpatched qt, and will be ignored.The switch --footer-html, is not support using unpatched qt, and will be ignored.QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-odoo'

the message is quite clear :
parameter --header-html is ignored,
so it is "normal" that I have no header in my pdf file

after that, I also got an issue about the wkhtmltopdf version, so I post the complete solution there : [[https://www.odoo.com/fr_FR/forum/aide-1/wkhtmltopdf-failed-error-code-6-message-the-switch-header-spacing-is-not-support-using-unpatched-qt-error-when-sending-mail-99853]]