Error message
English: VAT code is not allowed on the DATEV API
This error appears when exporting transactions, invoices or employee reimbursements from Moss to DATEV Unternehmen Online with unsupported VAT codes.
Why this error occurs
DATEV Unternehmen Online only supports a limited, predefined set of VAT (tax) codes via its API. Not all VAT codes that exist in DATEV can be transmitted through the integration.
Moss automatically provides the most commonly used VAT codes for:
Domestic purchases
Standard international purchases
If an invoice uses a VAT code that is not supported by the DATEV API, Moss automatically blocks the export and this error message is shown.
How to fix the issue
1. Identify the affected invoice
In the export summary, Moss highlights the invoice(s) that caused the error. The expense(s) causing the error are indicated in the error message with the amount, invoice number and supplier name. Open the affected invoice and check the VAT code / tax rate that is assigned.
2. Check whether the VAT code is supported by DATEV
Compare the VAT code used on the invoice with the official list of VAT codes supported by DATEV Unternehmen Online.
➡️ You can find the full list here (provided by DATEV): https://help-center.apps.datev.de/documents/1008613
If the VAT code is not listed and marked as accepted for accounts payable invoices, it cannot be exported via the DATEV API.
3. Use a supported VAT code (recommended)
If possible:
Change the VAT code on the invoice to a supported VAT code from the DATEV list
Save and re-approve the invoice
Retry the export
This is the most reliable way to resolve the issue.
4. Using custom VAT codes
If you require VAT codes that are not available by default in Moss, you can:
Add custom VAT codes manually in Moss
⚠️ Important: Adding a VAT code in Moss does not automatically mean that it is supported by DATEV Unternehmen Online.
If you use a custom VAT code and the export fails:
The VAT code may not be supported by the DATEV API
5. Contact Moss support for unsupported codes
Some VAT codes can be cleared on a case-by-case basis, if we can confirm that DATEV Unternehmen Online actually accepts them, even though they are not part of the standard supported set.
Please contact Moss Customer Support and provide the VAT code you are trying to use
Our team will review the case and advise on the best next steps.
Summary
DATEV Unternehmen Online supports only a subset of VAT codes via its API
The error occurs when an invoice uses an unsupported VAT code
Use a VAT code from the official DATEV-supported list whenever possible
Custom VAT codes may require manual review by Moss support
If you are unsure which VAT code to use, we recommend checking with your tax advisor or DATEV consultant before exporting.