Most common causes:
The project number does not match — the invoice has been posted with a different project number than the one registered in AIMZ.
The integration has not synchronized yet — AIMZ fetches invoices regularly, but it can take a few hours.
The invoice has not been posted yet — only posted invoices are imported.
A filter is active — check whether you have a filter in the invoice overview that hides it.
Contact AIMZ support via the chat if the invoice still does not show.