Use the following steps to solve the issue:

1. Check the max number of options the ranking question allows and make sure you have not exceeded the maximum.


2. Verify all options are using unique response labels.


3. If you’re using an Excel file as an answer option, the number of options should not exceed 500 unless if you are using an Office 365 subscription.


4. If the form is shared, ensure the sharee is not using an individual account.


5. Try to use the Save as Draft option and then open the form to check if the issue remains.