If your Coinbase balance showing 0, it could be due to a few reasons such as a temporary glitch in the app, a synchronization issue, or a problem with your internet connection. First, ensure your internet connection is stable. Next, try refreshing the app or logging out and back in to see if your balance updates. Check for ongoing maintenance or service disruptions on Coinbase’s status page if the issue persists. Additionally, ensure you have the latest version of the app installed. If none of these steps work, contacting Coinbase support for further assistance would be the best action.