This error (subcode 2490408) is a limitation of Meta's own API, not an Ads Editor bug: the combination of the Leads objective with a WhatsApp destination can't be created by any tool that uses the public API (only through Meta's own interface). Messenger works. WhatsApp doesn't.

What to do:

  1. If you want conversations on WhatsApp, use the Conversations / Messages objective (this works normally in Ads Editor). Ads Editor already offers it as an alternative when it detects this case.
  2. If you really need a lead form, keep the destination in the ad itself (instant form) or on your website instead of WhatsApp.

There is nothing to adjust in your account. This is a Meta restriction for this specific format.