I am a Product Support Specialist. I had this same issue today. I had the customer clear cookies and cache then relaunch the browser. We went back to Federal and went over the entries to double check entries and errors were found.
I would suggest trying those same steps because one wrong entry can affect what is populated for the taxpayer to fill out. Instruct the client to have the documents IN HAND or at least access to them online so they can make sure the information mirrors what their documents have on them. Especially because there can be errors when documents are imported into TurboTax. I would have the REVIEW the information for this reason.
Also make sure EACH QUESTION IS READ COMPLETELY. Also, suggest utilizing the in product assistance (most sections have a question mark and or a Learn More option that can help) Many times missing a key word will result in errors
