Should I build a Landing Page even when I'm not yet approved for the offer yet?
Yes. You get KWs, build out landing page you'll use then create ad copy and submit both landing page URL and ad copy when applying for an offer. If you don't get approved for the offer again, you'll want to reach out to your AM at the affiliate network directly. If the offer gets taken down, then it is no longer available for promotion, no matter if you're just starting to apply for it or have been running it for months. This is solely at the discretion of the affiliate network.