Send email error 0x800CCC0F with Outlook 2007

I have strange problem with Norton Security getting an error 0x800ccc0f to send mail only from an account. If I am connected to the network (ISP) account owner I can send emails without any problem. If I am connected to another third network (ISP) I can not send any emails from that account, getting the error 0x800ccc0f, except if I disable "Analyze the e-mail messages to send." Why I get errors only with third party ISP and Norton just stop sending e-mail through that ISP?
Best Regards
BDisp