You added new and/or modified existing poll options after some participants already entered their vote. Doodle would not know what your existing participants would have selected. Therefore it indicates the missing information with question marks. Simply ask your participants to update their votes based on the new information you added - you can read here for more info.
Alternatively, if you manually set the poll options to their original values, the question marks will disappear and the votes reappear. To do this, open the admin-link and click 'Edit'. Change the options to their original values and click 'Finish'. The question marks are gone now.
Before editing existing options that some participants already voted for, we recommend that you save the current state of the poll as a PDF file. See here how.