Another reason could be pending transactions or deposits. If you've recently made a trade or deposit, it might not show up immediately on your balance until the transaction clears. In this case, wait for the transaction to complete before expecting an updated balance.
If these steps don't resolve the issue, it could be a technical glitch on Robinhood's platform. Contacting Robinhood's support team via +1-855-998-0737 will give you the assistance you need. Make sure your app is up to date as well, as outdated versions can also cause syncing issues. Keep in mind that Robinhood occasionally performs maintenance, and this can temporarily affect your balance updates.