Shanghai II (SHA2), Beijing (BJS1), Beijing III (BJS3) Datacenter Issue

Zscaler is currently investigating reports of an issue with its Shanghai II (SHA2), Beijing (BJS1), Beijing III (BJS3) datacenters. We are investigating periods of slowness, connection timeouts and/or increased latency. If you’re currently experiencing any traffic impacting issues please failover to your secondary DC or any other alternate DC. For more information, please refer to the following support article. We will continue to provide updates here as the investigation progresses. For detailed updates, please check the Service Status section in your Zscaler customer support portal (CSP). Status changes and updates will be posted there as they become available.Latest Update - Mon, 05 Jan 2026 12:00:26 UTCZscaler has confirmed that the issue is external originated outside of Zscaler, We continue to actively monitor the affected data centers. If you continue to experience issues, please contact Zscaler Support so we can evaluate the required next steps.Update - Mon, 22 Dec 2025 08:24:46 UTCZscaler has implemented mitigation for the issue. Our systems remain fully operational, and we will continue to monitor closely to ensure ongoing stability.Update - Mon, 22 Dec 2025 10:58:22 UTCThe issue has resurfaced, impacting Shanghai II (SHA2), Beijing (BJS1), Beijing III (BJS3) datacenters with intermittent slowness, timeouts, and increased latency. We are investigating further and will share updates when available.Update - Mon, 22 Dec 2025 15:50:23 UTCZscaler is prioritizing the issue and is actively working to isolate the problem and identify the root cause. We appreciate your patience and understanding during this investigation. Additional updates will be provided as more information becomes available.Update - Mon, 22 Dec 2025 18:12:17 UTCWe have not yet received an update from the initial service provider we engaged. In parallel, we are working with another provider familiar with the issue to continue the investigation and determine recommended actions. We will share further updates as soon as more information becomes available.Update - Tue, 23 Dec 2025 03:30:02 UTCWe have not yet received an update from the providers we engaged. We are contacting them to confirm the recommended next steps and will share further updates as soon as additional information becomes available.Update - Tue, 23 Dec 2025 07:20:32 UTCWe applied a partial mitigation on the BJS3 ZSN cloud by shifting to alternate DNS resolvers and are observing the issue and related metrics. We are monitoring error rates and resolution latency, coordinating with external third parties, and will review the metrics to discuss the effectiveness of the change and decide next steps at the upcoming checkpoint.Update - Tue, 23 Dec 2025 08:37:37 UTCWe applied a partial mitigation in our Beijing (BJS3) environment by switching to alternate DNS resolvers, which has significantly reduced DNS errors. Validation confirms these resolvers successfully resolve the affected domains, whereas the previous resolvers were intermittently not able to get response from authoritative DNS servers. Some users may still experience intermittent issues. We plan to extend the change during the next off-peak maintenance window and will provide the next update as we proceed.Update - Tue, 23 Dec 2025 11:34:21 UTCWe continue to monitor the situation and validate the mitigation applied, while gathering customer feedback. We plan to extend this change during the next off-peak maintenance window and will provide the next update as we proceed.Update - Tue, 23 Dec 2025 17:49:25 UTCFollowing the successful partial transition from Zscaler-managed resolvers to alternate DNS resolvers, we saw a significant reduction in DNS errors. We are expanding this update to the rest of the nodes to improve the performance.Update - Tue, 23 Dec 2025 20:34:40 UTCZscaler continues to monitor service stability and validate the mitigation applied in impacted China data centers. Additional nodes have been updated with alternate DNS resolvers, and monitoring indicates improved DNS resolution behavior. Zscaler is actively reviewing telemetry and customer feedback to confirm continued stability. We remain engaged with the external third party to further investigate the underlying DNS behavior and will provide additional updates as progress is made.Update - Wed, 24 Dec 2025 01:54:23 UTCZscaler continues to monitor service stability and validate the mitigation applied in the impacted China data centers. Additional nodes have been updated with alternate DNS resolvers, and current telemetry shows improved DNS resolution. To help us confirm sustained stability, please reach out to support if you continue to experience DNS resolution issues.Update - Wed, 24 Dec 2025 06:06:06 UTCBased on customer feedback and internal monitoring, Zscaler confirms that the mitigation applied to specific nodes in the affected data centers has yielded positive results for DNS resolution. We will continue to monitor the situation and share incremental updates as the mitigation is rolled out across all clouds in the affected data centers.Update - Wed, 24 Dec 2025 18:06:17 UTCZscaler has received additional customer feedback indicating improved DNS resolution following the mitigation deployed on additional nodes in the affected datacenters. Services remain stable, and monitoring continues. Based on continued validation, Zscaler plans to extend the mitigation across all clouds within the impacted datacenters in a controlled manner. In parallel, our external third-party partner has indicated the issue may be related to an upstream network condition, and joint investigation is ongoing. Further updates will be shared as additional progress is made.Update - Thu, 25 Dec 2025 18:57:16 UTCZscaler continues to monitor service stability following the transition to alternate DNS resolvers in the affected data centers. No further issues have been observed since the change, and DNS resolution remains stable across monitored environments. Based on continued validation, Zscaler plans to extend this mitigation across all clouds within the impacted locations in a controlled manner. Monitoring remains ongoing, and additional updates will be shared as progress continues.Update - Fri, 26 Dec 2025 18:32:47 UTCBased on telemetry, Zscaler has observed stable service behavior following the transition to alternate DNS resolvers in the affected data centers. Zscaler plans to extend this mitigation across all clouds within the impacted data centers in a controlled manner as validation progresses. Engagement with our external third-party partner remains ongoing, with no new updates at this time. Further updates will be shared as meaningful progress is made.Update - Mon, 29 Dec 2025 04:14:00 UTCBased on ongoing telemetry, Zscaler continues to observe stable service behavior following the transition to alternate DNS resolvers in the affected data centers. We will continue the rollout in a phased manner as validation checkpoints are met.Update - Mon, 29 Dec 2025 17:52:25 UTCThe fix remains stable on the previously affected data center nodes, and we are actively planning deployment to the remaining nodes. We will share timeline updates as they are finalized.Update - Wed, 31 Dec 2025 00:18:05 UTCZscaler continues to observe stable service behavior following the mitigation applied to affected nodes in the impacted data centers. No new issues have been observed, and services remain stable. Our external partner has indicated that the investigation is ongoing and may involve upstream network behavior within China. Zscaler remains engaged and will continue to monitor service performance. Further updates will be shared as additional information becomes available.Update - Mon, 05 Jan 2026 12:00:26 UTCZscaler has confirmed that the issue is external originated outside of Zscaler, We continue to actively monitor the affected data centers. If you continue to experience issues, please contact Zscaler Support so we can evaluate the required next steps.