ODT Template not showing contacts

I need some help for the following issue. After having created an ODT template for proposals the contact information is not showing up. I carefully read through the wiki Create an ODT document template - Dolibarr ERP CRM Wiki, but all tags beginning with {contact_xxx} are not shown.
I able to select the contact/site address in the propopals menu.
Dolibarr version we are using is 18.0.0. All kind of input is highly welcome.