junk e-mail list error

I'm using Outlook 2007, and an error message comes up every time a send/receive is done:

Cannot add to the server Junk E-Mail Lists, you are over the size allowed on the server. The Junk E-mail Filter on the server will be disabled until your Junk E-mail Lists have been reduced to the size allowed on the server.

Would you like to manage your Junk E-mail Lists now?

I have clicked on "Manage Lists..." and deleted all the blocked senders, but the message keeps popping up.

I then logged into the Office 365 web client and tried to delete my blocked senders, but when I try to save the changes I get a message saying:

Junk e-mail validation error. Value: xxxxxxxxxxxx@earthlink.net.