The time zone problem about custom STS servie with WIF

Question

Hello,everyone.

 I completed a custom STS service with WIF.When i test it,i found that it worked well when i set computer time zone to UTM.But my time zone is UTM + 8.When i set time zone to UTM + 8,the argumentException about "ValidFrom"、"ValidTo" and "keyExpirationTime " occured.

I see that I can  solve  "ValidFrom" and "ValidTo" exception by   setting the  "LiftTime" property of the token when writing it.But I have no idea to the "keyExpirationTime " exception.

Can anyone help me!