Mail account doesn´t work!

[Hovestadt]

Don´t know if this is the right forum. Anyway I would like to know what you think is the best to do. I am not really an expert with computers.

I had filevault running on my computer but after I turned that off all my system settings were gone. I installed my set up my e-mail account new, but now only I can recieve emails, but not send anymore.
The online account of course still works but with the program mail I can´t send mails anymore althoug I put the same outgoing mail server like I had before. At least it stands so on my account paper.
When I want to send a mail this message this message appears:
"The attempt to read data from the server "mail.gmx.net" failed."
But on my paper stands that outgoing mail server(SMTP) is mail.gmx.net.

What do you think is the mistake and what should I do. Try the same account settings with another mail program?
But I want to keep the mail program really. Help is really appreiciated.

[Hovestadt]

Don´t know if thats help. I am on a macbook with Mac os X version 10.4.9 but I guess it is more of a simple problem.