If you can’t log in, this could be for the following reasons:
You are already logged in on more than five different browsers or devices. The system will only allow you to be logged in on five different devices, so you will need to log out of another browser or device before opening another.
It is possible that the details you have entered could be wrong. The best way to resolve this is by resetting your password. Please see the question I have forgotten my password – what should I do? for instructions on how to do this.
You haven’t activated your account. New joiners are asked to enter a valid email address that is 'owned' by them. Before you can access the site you need to confirm your registration by clicking on a link in an email we have sent to you. This email will normally arrive within a few minutes of your registration. See I didn't receive my verification email, what do I do? for information on what to do if you have not received this email or wish to resend it.