Good evening xiaobo, I would really like some more information here. Are you trying to connect and send your email from home, or do you mean you cannot send from the company? Either way what sort of connection are you using, dial-up, broadband or lan? And if you are trying to send from other than your company, which isp are you using?
Having asked those questions, I shall now have an educated guess at your problem. I suspect that you are trying to send from home, using a different isp than your company uses. If this is the case, then most isp's will only allow you to send email via their own mail servers (you can still download from others though). If the above is correct, then you have at least three possible solutions.
1, Change your isp and use the same as your company. 2. Change your isp and use one that will allow you to send mail via another isp's mail server (there are some who will allow this, but I cannot think of any off the top of my head at the moment). 3. Get an email account with your current isp, and route your outgoing mail through their server. Generally all you would normally need to do, is change the outgoing smtp details from RM easymails to the smtp address for your new account. Be warned though, some isp's, such as BT, have a separate smtp server for this purpose, so the details will not be exactly the same as your new account. If you need to go down this road, then check the isp's website fully!
If you use the last option, as long as you select the correct account when you write and send an email, it will to all intensive purposes appear to come from your work account. It will only show as different if someone checks the headers and runs a trace.
I hope this info helps, if not then please reply with the initially requested information and we can take it from there.
Regards, Mr. Mouse.