Windows updates KB5066131, KB5066835 and KB5065789, are breaking the Management Server functionality (troubleshooting)
The latest Windows updates (KB5066131, KB5066835, and KB5065789) are breaking the communication between the MOBOTIX HUB Management Server and IIS (Windows web server); as well as on standalone Recording Servers. There are some workarounds available.
Issue
The latest Windows updates — KB5066131, KB5066835, and KB5065789 — are breaking the communication between the MOBOTIX HUB Management Server and IIS (Windows web server). This issue has also been observed on standalone Recording Servers.
Symptoms
After installing Windows updates, the Management fails to start.
In the Management Server log (Server.log) log, the following message may be shown:
Error initializing VideoOS Management Objects Client Module: An error occurred while receiving the HTTP response to http://localhost/ManagementServer/ServerService.svc. This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details.
Cause
Further analysis reveals that the October 2025 Windows Cumulative Update (KB5066835) introduced a regression affecting certain HTTP/2 and loopback traffic scenarios. This may cause requests to fail or connections to drop unexpectedly when hosted locally using IIS, Kestrel, or other web servers relying on HTTP/2 by default. As the MOBOTIX HUB Management Server uses the Microsoft IIS, it is directly hit by the issue.
Workarounds
To work around the issue, please perform either of the 2 following options.
Option 1: Uninstall Windows Updates
Remove (uninstall) the follow Windows updates:
- KB5066131
- KB5066835
- KB5065789
Option 2: Disable HTTP/2
You can temporarily disable HTTP/2 on the affected system until a fixed update is released. You can do this by setting the following registry keys and restarting the machine:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\IIS\Parameters] “EnableHttp2”=dword:00000000 “EnableHttp2OverTls”=dword:00000000
Versions affected
All MOBOTIX HUB VMS versions are affected. We have confirmation for the 2022 R1 - 2025 R2 range, but other MOBOTIX HUB versions are likely to be affected, too.