You have not maintained Customizing for Document Type &1

What causes this issue?

Document Type <(>&<)>1 not mapped to Transition type in Customizing.

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?

You must maintain settings in
<DS:SIMG.SAFTN_AO_TR_TYPE>Assign Transaction Type to Document Type</>.
There, you assign your company's accounting documents a transaction type
which identifies this is a standard transaction, an adjustment, a tax
regularization or a calculation value.
For every <LS>Company Code</>, you must assign a <LS>Transaction Type
</>for every type of Accounting Document you maintain.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.