Flat tax rate: 'Amount type' must be void

Cause

The "Amount type" column of VAT codes for Flat tax rate method must remain empty. If an amount type is entered, the VAT form for Flat tax rate won't be calculated.

Solution

Delete the entry in the "Amount type" column and ascertain that your VAT code settings for Net debt/Flat tax rate are correct.

Refer the Swiss vat tax report/Flat tax rate page for further information.