Problem in sending e-mails since yesterday

I am using Outlook Express. I am facing problem in sending e-mails since yesterday. till yesterday i was able to send e-mail with my domain smtp address and port 26 but from yesterday i am unable to send e-mails. when i disable rich text (HTML) format and use plain text then i am able to send e-mails

when i connect to free link.net (WOLS)dialup connection then i am able to send e-mails even in both rich text (HTML) and plain text format very smoothly. so the problem is at the end of PTCL. is there anybody having/facing same problem.

here is the error.

An unknown error has occurred. Subject '', Account: 'khuram', Server: 'mail.supremefab.com', Protocol: SMTP, Server Response: '421 wagoneer.websitewelcome.com SMTP incoming data timeout - closing connection.', Port: 26, Secure(SSL): No, Server Error: 421, Error Number: 0x800CCC67

ANYbody having this problem

Bump

No problem, what-so-ever, with Microsoft Office Outlook 2007.

Shud not be a problem! Change the server port (if its urs) and try if it works! other than that no issue!

problem was at exchange, now solved.