FYI One of our customer's IT provider emailed the following to us:
As a heads up something in the latest Windows Update kills WebExchange.
We get an ERR_HTTP2_PROTOCOL_ERROR on all Browsers.
We managed to get it working by uninstalling KB5066835 and KB5065789
Seems to be an issue affecting ISS .NET sites.
windows - Why am I experiencing an HTTP 2.0 protocol error connecting to localhost web sites in IIS? - Super User
Localhost applications failing after installing "2025-10 Cumulative Update for Windows 11 Version 24H2 for x64-based Systems (KB5066835) (26100.6899)" - Stack Overflow
I don't know if there's a workaround yet from yours or Pegasus side.
