Hi PIP3
There are a few things to check for this error message:
- Check if there's any items in the quote with 100% discount. If so, please remove that item discount, convert the order, save the invoice, then re-add the discount line.
- Check if any items are used in more than 1 transaction lines in the quote, if so, please combine the lines for the same item to a single line, then convert the quote.
- If the above all checks out, please try clearing AccountRight cache.
If you have any further questions please feel free to let us know.