Copy the voucher number from the accounting system and paste it into the search field at the top of the invoice table. That way you quickly find the right invoice, even in long lists.
How to do it
Find the invoice in the accounting system and copy the voucher number.
Go to Invoice → Incoming Invoice.
Paste the voucher number into the Search field on the left above the invoice table.
The invoice appears in the list, and you can link or check it.
Can't find the invoice?
Check whether you have an active filter. A filter can hide the invoice even if the search is correct.
Check that you are on the right project.
If the invoice is brand new, it may not yet have been transferred from the accounting system.