In GRC Access Control 10.0, some users get email notifications while others do not get any notifications for Workflow, Firefighting activity or Provisioning. Emails are working for internal email addresses maintained in SU01 and not working for external email addresses (e.g. hotmail).
Please check with the IT/Network Team if they have a sniffer on the external email addresses, where users do not get any email notifications (for e.g; hotmail). Also check SCOT Settings.
The workaround is to change all email addresses in SU01 to the domain which is working. Also review all notes attached to the message for email notification issues.