vmware vsphere web client shows blank screen on windows 2012 r2 and flash player 19 installed

i have a closed test server system setup where i have a windows 2012 r2 and vmware vsphere web client installed with no external internet access.

vmware vsphere web client cannot work because it prompts it needs version 11 or higher.

i went to Adobe Flash Player 分發 | Adobe to download offline version of flash player

i installed it, and when i goto the vmware vsphere web client intranet website on my windows server, it just gives me a blank screen.

what can i do?