Invalid print character &

What causes this issue?

You want to create a billing document or a financial accounting
document. This is, however, not possible because the print character is
neither A nor B.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Maintain the printing character on the document header level. You do
this in Customizing for <LS>Cross-Application Components</>, under
<LS>General Application Functions -> Cross-Application Document
Numbering -> Argentina -></>
<DS:SIMG.J_1ACPA_LETTER4>Define Print Characters</>
.

Error message extract from SAP system. Copyright SAP SE.