Login Not Available
Last updatepostmortemAug 13 · 05:18 UTC
**Date:** August 10–11, 2026 **Affected service:** CalStudio \([calstudio.io](http://calstudio.io)\) sign-in **Status:** Resolved ## Summary Between 6:30 PM PT on Aug 10 and 4:45 AM PT on Aug 11 \(approximately 10 hours\), users were unable to log in to CalStudio. Login access has been fully restored. We're sorry for the disruption this caused to your work. ## What happened On August 10 at 6:30 PM PT, we enabled a new security rule on our shared sign-in service \([accounts.flukelogin.com](http://accounts.flukelogin.com)\) to address a rise in fraudulent account creation on [fluke.com](http://fluke.com). This sign-in service is shared across several Fluke applications, including CalStudio. The rule was intended to allow [fluke.com](http://fluke.com) traffic through, but it didn't correctly account for how CalStudio sign-in requests are routed — so those requests were blocked instead of allowed. ## Impact CalStudio users were unable to log in for approximately 10 hours, from 6:30 PM PT on Aug 10 to 4:45 AM PT on Aug 11. \[CONFIRM SCOPE — e.g., number/percentage of affected sign-in attempts, if you want to share a figure.\] Note: our internal incident remained open for an extended monitoring period afterward, since CalStudio had a separate product release the same night — that monitoring window is not reflected in the outage duration above, which covers only the time login was actually unavailable. ## Resolution Our team deployed a fix that restored login access within a few hours of detection. Before any similar rule is re-enabled, it will be scoped specifically to [fluke.com](http://fluke.com) sign-in traffic so it cannot affect CalStudio or other applications on the shared login service. ## What we're doing to prevent this from happening again 1. **Scoping security rules precisely** — future rules on the shared login service will target [fluke.com](http://fluke.com) traffic specifically, not the service as a whole. 2. **Testing across all consumers** — we're setting up test accounts for CalStudio and other applications on this shared service, so changes are validated against every consumer before going live. 3. **Requiring sign-off before changes ship** — no change to this shared service will go live without review and approval from the teams that depend on it. 4. **Strengthening our change process** with our infrastructure team for any future updates to shared authentication infrastructure. CalStudio access is critical to your calibration workflows, and we're committed to catching issues like this before they reach you. Thank you for your patience.
Reported by CalStudio on their status page.