In 26.1 the quarantine plugin is depricated. The quarantine emails are now native to DLP/Enforce UI
DLP 26.1 and above
Product improvements.
Go to Settings>General> select configure.
Enter in all values and save.
how to create client jks see: certificates kb
Setup Modify Email response rule with the header name and header value.
Create SMART response rule Release from quarantine
1. go to Manage>Policy>response rules
2. create a smart response rule
3. select release from quarantine.
Import certificates to the SMG console
enabled DLP Email connnect:
See: https://techdocs.broadcom.com/us/en/symantec-security-software/information-security/data-loss-prevention/26-1/using-cloud-services-to-prevent-data-loss/about-cloud-service-for-email/setting-enforce-email-security-cloud-quarantine-remediate.html