CAT_VALIDATION_ERROR_MOBILE_LINK_INVALID fires when the optional mobile_link URL is malformed. Snap routes mobile-device clicks to mobile_link when present, so a broken value silently degrades dynamic ad delivery.
Snap Catalog Manager validates landing-page URLs for crawlability, format, and uniqueness. Common triggers: invalid characters, relative paths, missing protocol, redirect chains, or hostnames that don't resolve.