IIS error 403.16 for HTTPs Connections - Help

Hi All,

I'm recently having issue of IIS and client connections after we upgrade and migrated from 2k3 to 2012r2 and iis from 7.5 to 8.5.

I'd look through many articles and tried many hints, most recent and relate to my issue like here: https://forums.iis.net/t/1232708.aspx?IIS+Client+Certificate+Mapping+Authentication+Is+it+possible+to+set+default+CA+

Or here:

http://stackoverflow.com/questions/27232340/iis-8-5-mutual-certificates-authentication-fails-with-error-403-16

But ALL FAILED.

Each time I tried I still got same error in IIS Logs:

443 - xxx.xxx.xxx.xxx HTTP/1.1 XXXXXXXXX 403 16 2148204809 1450 173843 5618

Can anyone help me please??