1040 Schedule B is needed to list out all the interest and dividends if either one is $1,500 or more. Did you have a lot of interest or dividends? Maybe the IRS got more 1099s than you entered?
https://www.irs.gov/pub/irs-pdf/f1040sb.pdf
If you print out your return is there a Sch B in it? Save the PDF
https://ttlc.intuit.com/community/saving/help/how-do-i-save-my-turbotax-online-return-as-a-pdf/00/26...
