Please double-check you're entering the correct credentials when trying to import. If you still can't connect, you will want to make sure that your TurboTax software is up to date. Please see the following TurboTax Help Article for assistance.
How do I update my TurboTax CD/Download software program?
You may also want to try clearing your browser's cache and delete cookies. A full or corrupted cache can keep TurboTax from functioning correctly when trying to connect to your web browser to import your documents.