Every time someone searches on Google, an auction happens in the background to decide which ads show and in what position. If your ad is losing those auctions, it shows up less often or not at all, even if your budget has money left. The signs are a low impression share and a high "lost impression share due to rank" metric. This means your ad quality or bid is not strong enough. The response is usually to improve the ad quality score by making the ad and landing page more relevant, or to increase the bid. So what do you think matters more in winning a Google Ads auction, the bid amount or the quality score?