TurboTax Premier 2019 - I had this same problem. I was not submitting any business return info. I was submitting Fed, Kansas and Missouri all for efile. I've used TurboTax for 10+ years, without ever having a problem. I could not get past this error after trying tons of things recommended on several posts, here and other sites. I even tried it on different networks but that didn't work either.
I finally tried installing TT on another computer, and it worked fine - first try. Both computers are Windows 10 Pro 1909. Both have latest updates. Both are running BitDefender (NOT disabled). I tried as both Administrator and not. Nothing could get my tablet to work with efile, but the first time I tried it on my desktop it worked fine. I have no explanation why, but if you have another computer you can install it on and then copy over your tax file I would recommend that.
