Dear All,
based on this documentation, I have set up all settings ...
https://www.odoo.com/documentation/user/11.0/sales/invoicing/time_materials.html#invoice-your-time-spent
If I want to invoice timesheets, the invoice status in the sales order is always "nothing to invoice". Therefore, I can not create an invoice, and the error warning "There is no invoiceable line" appear.
No idea, what to do to create invoices.
Best regards ... Thomas