Outlook 2003 says it sent mail but did not

I have a very serious problem when using Outlook 2003 SP2 to send email with attachments totalling more than 1 MB or so. The BIG problem is the system tells me the email was sent. The email is stored in the sent items folder. All looks normal, but the email was NEVER sent! No warning sign, no error message, nothing! I travel a lot so I switch over many different ISP and the problem is the same. Furthermore, I have a yahoo account, but also an account from the Company and the problem repeats itself accross email accounts. Any ideas how to solve this?

 

This is precisely the way I know the email has gone out or not, because of this problem I always copy myself and when I do not get the email, I know the email has not gone out. Maybe I did not explain myself clearly. Outlook says the email has gone out, it places the email, attachment and all in the sent mail folder, but actually the email never reaches any of the recepients on the list. Not only the attachment, the entire email just dissapears... However if I repeat this directly from the yahoo web portal, then no problem. Before using outlook, I used outlook express and never had this problem.

 

Steve:

I forgot to say, yes, if the mail is sent with no attachment it arrives with no problem, furthermore, if the total size of attachments is less than 1 MB it arrives with no problem. It is big attachments that pose a problem. However when I used Outlook Express this never happened. Plus I thought when the ISP blocked the mail, I would get a message either by email or something indicating this happened, and the serious thing here is I dont get any sign this had happened.

 

Outlook 2003 says it sent mail but did

I have tried to send large files temporarily from Outlook Express and it works with no problem. The problem presents itself with any type of file: jpeg, pps, ppt, doc, xls.