SAP Note 26040 - FF723 'Internal error in table SKFTABN'

Symptom:

FF723 'SYST: internal error in table SKFTABN' occurred under the following conditions:
- Postings are made to a company code with 'Tax base net'.
- In all items (thus also in the vendor items), the same tax code is explicitly specified (thus no blank and no **).
- The total of the vendor line items is zero (therefore the total of the G/L account line items must also be zero).
Example of such a document:
PKey Account Amount Tax
31 Vendor 100.00 V0
40 Expense 100.00 V0
21 Vendor 100.00 V0
50 Expense 100.00 V0

Cause and prerequisites
Solution
From the point of view of organization, split into invoice and credit memo or do not specify a tax code in the open item account line items (leave '**') or install the following advance correction

Additional key words

FB01, SAPMF05A, SAPLTAX1, determine cash discount