Template does not exist

What causes this issue?

The reference order does not exist. Either you entered the reference
order on the request screen, or it is assigned to the order type as a
model order.

System Response

It is not possible to copy the field contents from the reference order.

How to fix this error?

enter an existing order as reference, or
take out your input, or
check, if the model order for the order type you entered does exist

Error message extract from SAP system. Copyright SAP SE.