Kmail won't send

[#1]

I have just set up Kmail on Linux and can't sort out the send as it comes back
Sending failed:
Sendmail exited abnormally: sendmail: Cannot open mail:25
The message will stay in the 'outbox' folder until you either fix the problem (e.g. a broken address) or remove the message from the 'outbox' folder.
The following transport was used:
Sendmail
I had setup up relay.plus.net, but that hasn't workded.  Maybe I shouldn't put that.  Anyone know how I can resolve it?
Thanks
Tony

[#2]

Looks like it's not set to relay.plus.net
here are the settings http://www.plus.net/support/customer_service/using/settings.shtml
Can you post a screen shot of the settings with any personal info removed?

[#3]

I don't know Kmail but relay.plus.net is correct for the outgoing server. The incoming one is mail.plus.net.
You shouldn't have Secure Password Authentication set, or Outgoing server requiring Authentication.
Edit: Adie's typing quicker than me tonight!

[#4]

Quote from: TonyPhotoplus

I have just set up Kmail on Linux and can't sort out the send as it comes back Sending failed: Sendmail exited abnormally: sendmail: Cannot open mail:25

I suspect the use of Sendmail is your problem; Kmail doesn't require it to be able to send mail (and on a home machine Sendmail is best avoided like the plague swine flu). 
Try deleting the account you've set up and starting afresh  - but don't 'Use Sendmail'
If you don't have (or didn't choose) the option to use Sendmail, try disabling it on your system altogether.

[#5]

Thanks guys, I just gave up in the end and managed to transfer all of Thunderbird.  kmail I gave up on
Thanks
Tony