There could be various reasons why your Instacart account was deactivated following the background check. Instacart maintains specific requirements and standards for shoppers, and if any discrepancies or issues are found during the background check, your account may be deactivated. Common reasons could include inaccurate information, a history of serious criminal offenses, or driving violations that do not meet Instacart's safety criteria. If you believe there was an error or you have concerns, it's best to contact Instacart's support for clarification.