If you have registered but you cannot login, this may mean that your account is pending approval. Most organisations are configured so users with recognisable email addresses are automatically approved, but if your email address is not recognised, this may be a reason why your account is awaiting manual approval from the administration team.
If you are using a hotmail or gmail email address for example, then your account is almost certainly pending approval for security reasons.
A member of the administration team will need to check if you have a legitimate reason to use the system. Sometimes, it may be useful to email a member of the administration team separately to ask them about the delay.