Since you're using TurboTax Online, try closing TurboTax, then clear your browser's cache and delete your cookies. See the TurboTax Help articles How to clear your cache and How do I delete cookies? for guidance.
Then, close the browser and re-open it. Open TurboTax Online again and pick up where you left off.
And, if this doesn't work, your best bet may be to delete and re-enter your charitable contribution data.
