Form 1099-K from eBay results in an error on Federal review. A link to Schedule C is requested but it's not clear what needs to be entered to make it work. How to fix?

After entering a 1099-K from eBay, an error is generated upon Federal review. A link to Schedule C or another source must be selected but it is not clear how to do this in the form provided. Only the Schedule C field is active and it's not clear what should be entered in that field. Adding the dollar amount does not fix the error. Also, I have not Schedule C because I have no self-employment income or other 1099-K's to report. Thanks!