mass email not working

I'm having the strangest problem and I've gone over all of the programming and I can't figure it out. All of the email capabilities work in the entire site but the mass mail does not send emails. Notify, forgot password work fine. But when I try to mass mail I don't get any errors it simply tells me that it sent but I never get them. I've tried almost all types of emails and different things. I'm using speakeasy.net and they told me they have no restrictions and no authentication. Also tried to mass mail 1 member and that also did not work. I run Microsoft Exchange 2003 with speakeasy connector. Any help is greatly appreciated..

Thanks johncesta, but the logs are empty.  This has me baffled.