I want to connect from mkr1000 to my server using ssl, but can't connect.

I tried to test clientssl connect to arduino.cc ok, but my server(iop.axxx.com) failed connect
do you have any idea or help for ssl connect ?

environment
mkr1000
wifi101 firmware(19.5.2)
wifi101(0.14. 3)

iop.axxx.com(my server)
iis8.5 window 2012
comodo sha256

update SSL root certificate iop.axxx.com but can't connect