This issue appeared in version 8.3.4 and involved detecting the correct Internet Protocol (IP) address of the respondent. The bug would trigger the error message "Error #274 - Database error. Cannot insert history row". This error would prevent respondents from taking the survey. Only some server configurations (those that included proxy servers and load balancers) were affected by this bug. If you are running version 8.3.4 you should update your software to version 8.3.6 and re-upload your project. If data was collected from a respondent in 8.3.4, that data will still be available in 8.3.6.