I have the same problem. I sold a property and did not make large enough estimated payments to MN and they hit me with a penalty. The solution is to restart the filing process and select the state mail option. I printed the state (40+ pages) and will mail it in Monday. This may be a TTAX bug.
Another issue is that TTAX charges for E-file and then cannot do it. This is a billing problem.
Imagine my surprise to find out that this problem is nearly a year old. I have the same problem that you experienced in early 2019. Also as for you I cannot find a place to get a refund. My only recourse is contest the charge with the credit card company.
Just ran into this same issue... it's maddening that it doesn't flag it in the software until after you pay the filing fee and attempt to submit the return. When you're going through the MN return questions, it only says that you need to file by mail if you use the annualized income method to calculate the penalty.
This just happened to me too...have you found a way to get a refund for the State filing?
Please contact Turbo Tax support via phone to see if there are any possible workarounds that they can help with; contact details can be found here.
Request Turbotax to refund the amount they charged you: