I had the same problem. Here's what worked for me:
- go to "forms" and open "1040/1040SR worksheet"
- click on line 10 b
- this opens up a worksheet containing all of your cash charitable donations. In my case these added up to more than $300.
- add a line, donating to the fictitious charity "Turbotax is stupid". Put in a NEGATIVE amount so that the sum of all the contributions equals $300 exactly.
- close the worksheet
