In the course Applied Accessibility, the questions Improve Chart Accessibility with the figure element and the question Wrap Radio Buttons in a fieldset Element for better Accessibility. You can resolve but the server doesn’t accept the answer in any way, you need to skip the question and follow with the next question.
I just tested both of these and they worked fine for me. As @jaydog said, we would need to see your HTML in order to help you. My advice would be to click the “Reset All Code” button for each one and then only make the changes asked for in the instructions. In both cases it is as simple as replacing one element with another.