How to Troubleshoot TurboTax Transmission Error?

This error usually occurs when your TurboTax account goes on billing hold, or the pay with My Refund accidentally adds twice to your shopping cart. However, this issue is technical and occurs through your computer and internet connection. Still, it requires an instant fix. But if you notice the status of your tax return being pending or rejected, it’s not a transmission error.

Source: TurboTax transmission error