emails stuck in outbox ntlworld account

Hi,

I have a problem with outgoing email on my ntlworld email account which from searching on here seems to have happened to others. I can receive emails but have not been able to sent for several days now (there doesn't seem to be a response from the server). I wonder if the settings on the outgoing server need changed, but if so what to?

the outgoing server settings are 

SMTP server smtp.virginmedia.com

Security type SSL

Port 993

and the 'requires authentication to send emails' is on. 

Can anyone help. I contacted the virgin media chat function but they have been no help at all? 

Thanks