Short answer
Call FirstNet's Rapid Response desk, which operates 24/7 and takes tickets by email, phone or portal. Platform issues are escalated to Mimecast or SendMarc by FirstNet, so you never deal with the vendor directly.
In detail: Mimecast and SendMarc email security support
How the support path works:
- Rapid Response is the single front door for incidents, service requests and everyday needs such as releasing a quarantined message
- FirstNet's managed service covers policy tuning, threat triage, user release workflows, DMARC programme management, archive search support and continuity activation where contracted
- Product issues that need the vendor go to Mimecast engineering through FirstNet under the Mimecast Elite MSP Programme
- SendMarc platform escalations are routed through FirstNet, and authentication changes follow a joint process: FirstNet specifies, your administrator executes, FirstNet validates
- Impersonation events found in SendMarc forensic reports or by Sophos MDR feed into FirstNet's incident response workflow
Response, resolution and availability targets are defined in your contracted SLA. Always log a ticket first, because escalation runs through FirstNet's service management from there.
Source: FirstNet Email Security & Threat Protection service page →