Outage report · Major outage

Hiver outage on May 4, 2026

Hiver email synchronization is experiencing a downtime.

SeverityMajor outage

StartedMay 4, 2026, 17:48UTC

ResolvedMay 5, 2026, 01:42UTC

Duration7h 54m

What happened

Hiver reported a major outage starting May 4, 2026, 17:48 UTC, affecting Email User Experience, Email Sync. It was marked resolved at May 5, 2026, 01:42 UTC.

The incident lasted 7h 54m from first report to resolution.
It was the longest significant outage Hiver reported in the 12 months up to it.
Hiver had reported 2 other partial or major outages in the 90 days before it.
4 other vendors we track reported a significant incident within 12 hours of it.

Latest update from Hiver

# **Incident postmortem: Email Sync Delay in Shared Inboxes** > Total downtime > > **6.5 hrs** > > Uptime in May 2026 > > **98.95%** > > Prior 12-month avg uptime of Hiver Services > > **≈ 99.98%** **What happened** On May 4, 2026, new incoming emails stopped appearing in Hiver shared inboxes for approximately 6.5 hours. The root cause was an unexpected and severe surge in message queue volume that overwhelmed a core infrastructure component — the Sync Engine — responsible for pulling emails from Gmail into Hiver in real time. Hiver's infrastructure is designed to handle up to 2× our peak traffic at all times. This is one reason we have maintained near-perfect uptime over the past two years. On this occasion, the surge exceeded even that ceiling, bringing the Sync Engine to a near-complete halt. **What we've done immediately** Our engineers have done a deep analysis of this incident. As a remediation step, we have added more elasticity to the message queues infrastructure so that

Read Hiver's official incident report ↗