Degradation with international destinations from Beijing, Beijing III, Shanghai and Shanghai II Data Centers

Zscaler is currently investigating reports of an issue with its Beijing, Beijing III, Shanghai and Shanghai II data centers. 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.Root Cause: third-party congestion impacting international upstream provider connectionsLatest Update - Mon, 04 May 2026 14:36:38 UTCWe are continuing to monitor service performance in China. Recent data shows a significant improvement in latency and page fetch times compared weeks ago, with performance levels now stabilizing. We will continue to monitor closely and provide further updates as more information becomes available.Update - Thu, 23 Apr 2026 11:32:02 UTCZscaler has verified that our data centers and infrastructure are operating as expected. We have observed packet loss on certain external network paths, and we are working with our network partners and the relevant ISPs to investigate further. We have also received reports from multiple customers that performance has improved. We will continue to monitor closely while we await additional findings, including any confirmation of the underlying cause.Update - Thu, 23 Apr 2026 15:24:56 UTCCongestion was reported by two third-party ISPs in China impacting their international upstream provider connections. Based on this feedback and our internal telemetry, service is now stable and the issue is considered resolved.Update - Fri, 24 Apr 2026 05:25:30 UTCZscaler data centers and core infrastructure remain healthy; however, we are again observing packet loss on select external network paths and hence have reopened this trust. We have confirmation from our network partners that their upstream path is again experiencing congestion towards international destinations.Update - Fri, 24 Apr 2026 14:32:51 UTCOur partner has confirmed that this is caused by network congestion during peak traffic hours. We are monitoring the situation and will provide updates as they become available.Update - Mon, 27 Apr 2026 05:07:32 UTCAs peak traffic hours have begun in China, we are again observing congestion and associated packet loss on select external network paths. Zscaler data centers and core infrastructure continue to operate normally with no issues identified within Zscaler DCs. Our network partners have confirmed this is related to backbone/upstream links (as referenced in previous updates) impacting connectivity towards international destinations. We are actively monitoring and working with our partners/ISPs, and will provide further updates as available.Update - Tue, 28 Apr 2026 06:58:20 UTCZscaler data centers and core infrastructure continue to operate normally, and no issues have been identified within Zscaler DCs. We continue to observe intermittent congestion/packet loss consistent with the previously reported backbone/upstream link congestion impacting connectivity to international destinations from China. Our provider has shared that they are actively working with their upstream carrier on possible network optimizations. At this time, no estimated time to restore has been provided. We will continue to monitor closely and provide further updates as more information becomes available.Update - Mon, 04 May 2026 14:36:38 UTCWe are continuing to monitor service performance in China. Recent data shows a significant improvement in latency and page fetch times compared weeks ago, with performance levels now stabilizing. We will continue to monitor closely and provide further updates as more information becomes available.