I am not use to oulook express, its been around 5 months I started using it, today morning I was able to send and recieve my emails but suddenly I am getting this error while sending mails. I am able to recieve the mails but cant send it. The error is
"The message could not be sent because the server rejected the sender's e-mail address. The sender's e-mail address was ''firstname.lastname@example.org". Subject 'check', Account: 'pop.1and1.com', Server: 'smtp.1and1.com', Protocol: SMTP, Server Response: '530 Authentication required', Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78".
Please help me, this is bugging me, you can suggest me another forum, where I can get an answer to it.