Open edx lms can't submit answer

We are trying to customize the Open edx ironwood version. when logged in as a staff in the studio,
1 Open a Course Outline
2 Create a Section, Sub-section, and Unit.
3 In the “Add New Component” interface, click the “Problem” button and select the “multiple choice” or “dropdown”
4 Create the question
5 Then publishing the question
When logged in as a student in LMS, While answering the question then click the submit button there shows an error like
“We’re sorry, there was an error with processing your request. Please try reloading your page and trying again.”
In my log I am getting the following error:
“Unknown error when dispatching problem_check to block”

Hello @divya.vishnu.

Could you please extract python traceback from logs and share? It should follow the error you mentioned.