Strange, if i look at the technical details it says this:
www.5dices.co uses an invalid security certificate.
The certificate is not trusted because no issuer chain was provided.
(Error code: sec_error_unknown_issuer)
But probably is a problem on my side
Which browser are you using and when did you update it for the last time?
The issuer is StartCom Class 1 Primary Intermediate Server CA and if you are using an old browser this CA might not yet be included (it works whitelist based so new CA's are not recognized by old browsers). My most recent Google Chrome 28.0.1500.95 accepts it though so it's probably a legit CA.
EDIT:
StartCom is quite an old CA so your browser must be ancient (or really configured poorly)