Sending mail from Windows livemail

Environment:

Win7 Home

Livemail Client

Service provider TALKTALK

IMAP set-up

My emails have suddenly stopped being sent, They appear in the sent folder and are timestamped. As the folder is kept on the server I assumed that once

there they would have been actioned.

According to my service provider:

My setting are OK (Servers port etc)

there is no problem with their service as my email accounts work ok from their web interface.

Therefore the problem is with the MICROSOFT server I am using to send emails ?? I was told that Email go to a microsoft server then to them.

Surely they are taling out of their *********

Sorry if this seems a silly question but I am at my wits end.

Thanks