Clicks without leads means the ad is writing a check the landing page can't cash. The usual suspects, in order: the page doesn't match the ad's promise, the page is slow or broken on phones, the action is buried or high-friction, or the traffic itself is junk searches the ad shouldn't have matched.
Diagnose with two looks: the search-terms report (were these even the right searches?) and your landing page on your own phone, clicked from the actual ad (does the promise carry through? can you convert in 20 seconds?).
Also confirm you'd know: broken conversion tracking makes healthy campaigns look dead. A test form-fill that shows up in your tracking settles whether it's a converting problem or a counting problem.