I can receive mail with kmail but when i try to send mail i get ,

Sending failed:
The server did not accept the sender address.
The server responded: "Bad address syntax "
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.
Note: Other messages will also be blocked by this message, as long as it is in the 'outbox' folder
The following transport protocol was used:
smtp.comcast.net

Anyone know what to do all my other email clients work except kmail.

I'm having this too

Nm, Its fixed I left off the domain

just because I'm curious...

Did you change your sender address to anything unusual?
Did you change your sender address at all?

Sometimes the sender address accidently gets set as your mail address on your local box like wonderfulme@sillyboxname.
Some smtp servers will accept any sender address you care to throw at them. Some demand that a sender address must be a valid address that actually exists.

Cheers,
Jan