I was getting this error as well, tried to see the details of the error in the Developper tools. It turns out the forms in fidelity are not ready yet. TurboTax could have listed a more explicit message because they are getting the error details from Fidelity.
Fidelity is returning the 400 response code with the following message detail:
{statusCode: 400, code: "FDPVLT-3008", type: "SYSTEM", message: "downstream service error: fpo",…}
category: "general"
code: "FDPVLT-3008"
code: "FDP-907"
message: "1099 forms not yet available for user ID There is no tax data for tax year 2020 from Fidelity Investments to import. If you have any questions, or need assistance, please contact Fidelity at [phone number removed].
message: "There is no tax data for tax year 2020 from Fidelity Investments to import. If you have any questions, or need assistance, please contact Fidelity at 1-800-544-6666."
Once the forms are ready in Fidelity this error should go away.
