Hi,

The error "Missing required account on accountable line" occurs because Odoo needs an account to post an approved expense. Even when using manual cash payment, each expense line must have an Expense Account and an Expense Outstanding/Payable Account to create the necessary journal entries. Without these, Odoo cannot complete the approval process.

To resolve this, check that your expense products have an Expense Account set and that the Expense Journal has a default account configured. On-premise Odoo 19 requires at least a minimal Accounting setup for the Expenses module to function properly. Without installing or activating the Accounting module, the system cannot find the accounts to post approved expenses, causing the validation error.

Hope it helps