c# - Certificate error when calling WCF service from Windows Service -

i have wcf service hosted on iis7. service called both silverlight client , c# windows service. @ moment running on same machine. uses self-signed certificate, authority .cer file imported trusted root using certmgr.msc

the silverlight app can call service fine, when windows service tries call it, following exception:

system.servicemodel.security.securitynegotiationexception: not establish trust  relationship ssl/tls secure channel authority 'localhost'. --->  system.net.webexception: underlying connection closed: not establish  trust relationship ssl/tls secure channel. --->  system.security.authentication.authenticationexception: remote certificate  invalid according validation procedure.     

what reasons windows service denied access while browser , silverlight app can access service on https? maybe because client certificates thumbprint must tied windows service or something?

(i'm kind of new workings of ssl authentication can see).

thanks

i found problem. turns out had imported ca current user store , not local computer store, windows service couldn't find it.