Why do I see the error "ERROR OCCURRED WHILE SUBMITTING FORM"?

Why do I see the error "ERROR OCCURRED WHILE SUBMITTING FORM"?

Check if you have any hidden fields in your form. If yes, check whether any validations such as No duplicates, Range/ Value validation have been configured for the hidden fields. When the value in the hidden field does not match the validation, an error message is displayed.

Make the hidden fields visible in the form and test the submission to find the field which is causing the error.