Sorry that you can't login. :(
This is probably due to either your password and information being incorrect.
Your information on the system has changed.
Your vivo admin can also reset it for you.
Here is a guide how to reset your password.
Reset your password
If you have forgotten your password and need to reset it, click on the sign in button on www.vivoclass.com.
Click on the forgot your password?
Then it will ask you to enter your email.
Check your email and follow the link. It will them prompt you to enter a new password.
If you cannot remember your email or password, ask your vivo administrator to reset it for you.
How do I update my password?
Log in and go to "edit login" in the top right hand corner. Here you are able to change your password.