You need to be logged into the marketplace in the same browser where the Closo extension is installed. Closo doesn't store your marketplace password — it just rides along with your existing session.
Steps
Open Marketplaces in the seller dashboard, switch the toggle on for the marketplace you want (for eBay or Shopify, click Connect), then complete its login flow in the new tab. The card shows your user ID and user name when Closo can see your account.
Open MarketplacesWatch the step-by-step video guide