The problem is rarely the click itself
Clicks mean the creative earned attention. The break usually happens after the customer arrives in WhatsApp: the promise changed, the first message did not pick up the ad's context, or the conversation went straight to selling. Check that the promise and the first exchange are continuous before buying more traffic.
Five places the sale breaks
Work through them in order: the creative's promise, the entry message, the first round of qualification, the timing of the quote, and the follow-up on silent leads. Change one at a time, or you will not know which change worked.
Three numbers that locate the real problem
Split the funnel into ad clicks, arrivals in WhatsApp, and completed key sales actions. One conversion rate per layer tells you whether the loss is in the creative, the handoff or the conversation.
Change one break in the next test
Hold audience and budget steady. Replace one creative promise or one opening reply, then record the WhatsApp arrival rate and the key-action completion rate.