Normally you cannot e-file Federal if you have no taxable income to report.....and SS income doesn't count.
Here's what you do if you think you need to file.
Go back to the Federal Wages&Income area. Create a 1099-INT from your bank with $1 of box 1 bank interest in it. (If you bank records indicate more, go ahead and round up higher) but make sure it's at least $1.
Run your Federal and state error checks again and try filing now.