This is a spontaneous connectivity issue that usually resolves itself if your connection to TurboTax remains intact while the process you are working on completes.
If the issue doesn't resolve on its own, close TurboTax, restart your computer, and reopen TurboTax.
If that does not solve your problem, consider some other things you can try:
- Reset your wireless access point and try logging in again
- Turn off your computer, your router, and your cable modem, in that order
- Wait a minute, then turn your modem back on
- Wait another minute, then turn your router back on
- Once your router is back up, turn your computer back on and try logging in again
If none of these things resolve your problem, you can also contact TurboTax customer support at https://support.turbotax.intuit.com/contact/