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SIM Provider Service Degradation RCA#

Incident date: 2-3 June 2026

Summary#

Multiple devices temporarily lost mobile data connectivity because of a service degradation at the SIM card provider. During the incident, affected devices appeared offline in Control Center, so configuration and monitoring for those devices were not available.

Device-side operation continued normally. Communication with traffic light controllers was not affected, and events were cached locally on the devices and delivered after connectivity was restored.

Impact#

  • Multiple devices were shown as offline in Control Center.
  • Device configuration and monitoring were temporarily unavailable for affected devices.

No Impact#

  • Affected devices continued to operate normally.
  • Communication with traffic light controllers was not impacted.
  • Events were cached locally and delivered after connectivity was restored.

Timeline#

  • 2 June 2026, 05:15 CEST: Monitoring detected an unusual drop in connected devices.
  • 2 June 2026, 05:29 CEST: Investigation started.
  • 2 June 2026, 18:54 CEST: The SIM card provider opened a high-priority service incident.
  • 3 June 2026, 04:50 CEST: The SIM card provider resolved the service issue and device connectivity started to recover.
  • 3 June 2026, 05:27 CEST: Monitoring showed that the number of connected devices had returned to the previous level.

Root Cause#

Affected devices could not maintain mobile data connectivity because of a service degradation at the SIM card provider. The detailed provider-side root cause is pending and will be reviewed once the SIM card provider publishes its RCA.

Resolution#

The SIM card provider restored the affected service. Devices reconnected automatically as mobile data connectivity became available again. Locally cached events were delivered after the connection was restored.

Follow-Up Actions#

  • Request and review the RCA from the SIM card provider.
  • Review whether provider-side service degradation can be detected and escalated earlier.
  • Review customer-facing communication for provider connectivity incidents.

Last updated: 3 June 2026, 05:27 CEST