There can be plenty of reasons why you can't log in.
Firstly, does your school use a custom login? If so, there isn't much that we can do. You'll have to get in contact with someone at your school to figure out what is wrong. We do not have any control over how your school logs you in if they use a custom login.
If your school uses our official login, then you need to consider these following statements:
If you think there is a technical problem, or something we haven't covered, you can always get in touch with us and we'll talk to you directly to see what the problem is. Contact us via email at [email protected]