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:
If none of these things resolve your problem, you can also contact TurboTax customer support at https://support.turbotax.intuit.com/contact/
This is a somewhat disconcerting message to see when (several years ago) someone attempted to use Turbotax to fraudulently file my return. When the error popped up I followed the link to get more info. When the web page came up it said no help was found. That should be fixed. A link that states it is to a page with more help should actually link to a page with more help
These instructions DO NOT WORK! Help Me Now!
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:
If none of these things resolve your problem, you can also contact TurboTax customer support at https://support.turbotax.intuit.com/contact/