Error while trying: CurrentInvoice_Book

Hi,

after CurrentInvoice_Create, CurrentInvoiceLine_Create, CurrentInvoiceLine_SetProduct, CurrentInvoiceLine_SetDescription, ..unit and price I call CurrentInvoice_Book.

Result is always: Economic.Api.Exceptions.ServerException(E00000): An internal error has occurred.

Example-error-id: 3f4a6cc3-0a2e-4a39-949c-bcf25ce3de8a

On the webInterface I see a booking was created - but it´s complete empty.

Maybe you know what is missing.

THX @ all