Accessing Web Service with certificate

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Hi,

I'm trying to add web reference to my project and getting back following
message:
"There was an error downloading
'https://webservicestest .com/services/SubscriptionSer vice/v1/'.
Unable to connect to the remote server
A connection attempt failed because the connected party did not properly
respond after a period of time, or established connection failed because
connected host has failed to respond"

I copied URL above into IE and getting page not found message.
I tried URL above on another PC and I'm immediatly getting in IE prompt for
choosing certificate.

Any ideas how to resolve this issue on my PC?

Thank you,
Victor