Grain: MS Calendar Sync Outage
Timeline of updates
- resolved
From 05/18 ~21:30 UTC until 05/19 ~10:00 UTC, Microsoft calendars were failing to sync due to an expired Microsoft OAuth Client credential. Due to the nature of the failure, alarms were not correctly setup which lead to the delayed resolution.
The sync failure led to some events not having their auto-record rules applied if the event was created or edited during the outage window.
The team has put in place mitigations to prevent this failure state in the future.
Archive proof
Rewindex commits each version of an incident it captures to a daily checkpoint, chains it to the day before, and has the checkpoint timestamped by FreeTSA and DigiCert. That proves this record existed by then and has not been changed since, by anyone, Rewindex included.
How the archive is checked, and what it cannot prove.
First version captured
In the 2026-10-17 checkpoint, timestamped by FreeTSA and DigiCert on . Record hash
e14efe74d6f9f9d0…
Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab).
Cite this
Status incident (vendor impact label: none) posted by Grain, started 2025-05-18 21:30 UTC, resolved after 0 min, 1 update(s).
- Title
- MS Calendar Sync Outage
- Vendor
- Grain
- Date
- URL
- https://rewindex.com/company/grain/incidents/vpxnb2mml5s3
Grain profileRecent Grain incidentsAll outages on May 18, 2025Grain in May 2025MarkdownJSON