I think what is happening is the system was not fully complete prior to it being opened up for 2020 filings. Of course the IRS will not begin accepting e-file until middle of February. I had fully completed my 2020 taxes, and got to the end where it said there were several forms that were not available from the IRS just yet, and when they were finalized and available, I would be able to file my taxes. It gave me the option to "pay today, and lock in my price." Didn't do that. Couple of days later, realized I had entered some inaccurate information. Tried to login, and it would through the "oops" error. Looked online, and said it was to be resolved by 1/29/2021. Logged in that day, and could make my update. Tried again yesterday (and today), only to have the "oops" error rear it's ugly head.
Throughout my process, there were several issues. (For one, asking me to verify the address of my solar equipment install, when I don't have solar, nor did I indicate that I had solar.) So, I don't think it's ready for primetime. Issues with TurboTax itself, and issues with last-minute changes that the IRS is making to forms.
