While pushing the offense from QRadar to ServiceNow we are getting "Encountered error creating Security Incident in ServiceNow".

Assign the roles "sn_si.integration_user" and  "sn_si.read" role to the configured user in QRadar.

https://docs.servicenow.com/bundle/istanbul-security-management/page/product/qradar-integration/task/configure-secops-qradar-add-on.html