- Which version of QlikView are you using?
- Are the IE Plugins supported by the OS? (requirements for each version in the release notes or system requirements in the download site)
- Are Plugin and Server the same version?
Tunnelling happens when port 4747 is not open from server (inbound and outbound) to client or in the client inbound and the protocol falls back to QVP over HTTP (port 80). You can enable always tunnelling in the QMC, but you cannot disable it.
Product name: QMS Backend Core x64
Client Build Number: 11.20.12235.0 (SR5)
I am not able to find technical specs for SR5, only SR3, but I have found several threads indicating that IE11 and Windows Server 2008 is supported by version SR5 which is what we have installed.
I am assuming the Plugin and Server are the same version because the Plugin is deployed with the Server install, and I do not know of a way to change it.
I have found a couple of threads indicating that this issue may have been resolved with SR6, but I have yet to confirm.
I have asked the end users to uninstall the Plugin and this avoids the issue, but this is only a temporary workaround.
If ports are not the issue, then I would suggest to contact Qlik Support, who very likely will ask you to upgrade to the latest version (SR16) and test then.
As for the system requirements of SR16, here they are (they may change in future releases): https://da3hntz84uekx.cloudfront.net/qlikview/11.20/13507/QlikView%2011.2%20SR16%20System%20Requirements.pdf
For what it's worth, here are the requirements for SR5, I would also suggest you double check them with Qlik Support: https://da3hntz84uekx.cloudfront.net/qlikview/11.20/12235/QlikView%2011.2%20SR5%20System%20Requirements.pdf