There are different factors that may cause this. Here are some things to consider and do to address the situation
In the beginning, select the type of error message that appears when you try to log on.
What can you do?
1-Check back for information (telephone/email number) and the password you are using.
2-Close and restart your browser, then try signing in again.
3-Check your connection and make sure you're connected to the Internet.
4-Try using a different browser (we recommend Firefox or Chrome).
5-Update your browser if you have done so yet.
6- Clear your browser's cache and cookies.