Error decrypting authentication ticket

[Guest]

Hello,

I'm getting an exception ("ticks must be between datetime.minvalue.ticks and
datetime.maxvalue.ticks") when I decrypt an authentication ticket stored in a
persistent cookie.

Both the ticket and the cookie are set to expire at datetime.maxvalue. If I
set the cookie to maxvalue and the ticket to, say, today + 60 days, I'm fine.

Any ideas on why I can't set both of these to expire at max value?

Thanks,

Bill