Live / Incidents / Fourth
Fourth: Critical Incident - Single Sign On - "Sorry, but we're having trouble signing you in.", Error
Fourth · fourth.comImpact: criticalinvestigating2026-10-01 17:46 UTC
Public — what happened
Summary
We are aware of a critical incident that may be affecting some of our customers.
We are continuing to investigate to determine the root cause of the issue.
Status and updates will continue here every 30 minutes until the incident has been resolved.
We apologise for this disruption to your service
Timeline
- Started — 2026-10-01 16:23 UTC
- Last update — 2026-10-01 17:46 UTC
- Ongoing at last check.
With SquidGrid — where it starts on the route
Independent path health
The status page is the symptom. SquidGrid measures the paths that reach Fourth against their own baselines — whether the routes carrying your traffic degraded, at which handoff, and who owns that stretch.
🔒 Sign in to seeCustomers get the live Provider Assessment Report for Fourth: its full incident track record, what tends to break, and recent public reports of problems.
Included with any paid plan.
Open the Fourth report →