Do you know if there is a limit of contacts to send a mail? I've created a group with 126 contacts in the Windows Mail, and it's always failing the sending... :confused:

Some Internet Mail Providers limit the number of addresses that can be on a message. They do this to prevent spammers from using their facilities.

If this is the problem, you can get an e-mail address from Google (g-mail), Hotmail, or Yahoo and send through them. Windows Mail can be set up to retrieve e-mail from these services (you have to configure the services, themselves, through your web browser). If you don't want to switch e-mail addresses, you can usually forward e-mail from your current ISP to one of these services.

I've set up a number of friends' accounts to work this way. They send through g-mail when they want to send to large numbers of people. g-mail also has pretty good spam filters.