I can receive emails but suddenly I cannot send or reply to emails. The error message I receive using Windows live is as follows :
It looks like the server marked your account as spam, which is why it is banned.
Have you tried sending out emails via Post Office?
Try to check these step-by-step troubleshooting on this article that we made, Cannot Send Email Rejected by the Server/Banned from using SMTP.
Let us know how it will go.