Segwise only ingests ads that are currently active — ads that received delivery or spend in the last 7 days. Paused ads, or accounts with no recent spend, won't show. This is expected, not a bug.
Just connected? New data appears after the first processing cycle, which runs once every 24 hours — so a new connection can take up to a day to populate.
Still nothing after 24 hours with active, spending ads? Share a screenshot of your dashboard (with your org and ad-network name) and we'll investigate.