Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
My first guess as to how to solve the problem is the simplest possible: set your computer's time and date with accuracy. The date, at least may be wrong - if the year is wrong, it can disable some functions of communicating with encryption.
After that... if that, set to the correct value, does not cure the problem, then tell me what web browser you are using (e.g. Internet Explorer, Firefox, Safari, etc.), on what computer platform (e.g. Windows, or Apple ...) and I will advise you further.