If users on your Qlik Cloud tenant are experiencing frequent WebSocket disconnections (Error 1006) and your organization has an IP Allow List configured, IPv6 may be the root cause. Qlik Cloud's IP Allow List feature currently only supports IPv4 addresses. When users connect via IPv6, their traffic does not match any entry in the allow list, causing the connection to be dropped.
Symptoms
Users experience random disconnections while working in Qlik Cloud apps. The error code reported is Error 1006 (WebSocket disconnection). The issue affects multiple users simultaneously and is not tied to a specific app or sheet. The problem is more prevalent after network changes or in environments where IPv6 is enabled by default.
Resolution
Qlik has confirmed they are adding native IPv6 support to the IP Allow List feature. The estimated delivery is between Q4 2026 and early 2027. You can follow the progress and vote on the ideation item here:
Work with your IT or network team to disable or restrict IPv6 on the network infrastructure used to access Qlik Cloud. This forces client connections to use IPv4, which is properly handled by the IP Allow List. Once IPv6 traffic is restricted, users should no longer experience WebSocket disconnections caused by this issue.
Cause
Qlik Cloud's IP Allow List feature only evaluates IPv4 addresses. When a user's device connects over IPv6, the source address does not match any entry in the allow list, and the connection is rejected or dropped at the WebSocket layer, resulting in Error 1006. This is a known platform limitation. Qlik has confirmed they are adding IPv6 support to the IP Allow List feature, with an estimated delivery between Q4 2026 and early 2027.
