The product is ready but there are no customers — this is very common in IT, because many teams focus everything on the product and leave marketing for last. As a result the product exists, but the market has no idea.
First question: is there demand?
Sometimes the product is good but its demand was never tested. You can test it fast and cheaply: run ads with a specific offer and see whether people are ready to pay. If demand is confirmed — scale; if not — change the offer or positioning.
Second question: are you going to market correctly?
If demand exists but customers aren't coming — the problem is in market entry (Go-to-Market). You need clear answers to: for whom, through which channel, with what offer. A complex product isn't sold with one ad — trust is built first (content, cases), then the sale.