Microsoft Outlook/Outlook Expres is unable to Download morethan 8MB Mails

Hi,

I have a problem for downloading high capacity mail(More than 8MB)in Microsoft Outlook/Outlook Expres .

I have Lotus Domino Server with the settings of 15MB Mail limit. Whenever I am trying to download a high capacity mail thru Microsoft Outlook/Outlook Express its progress is going up to 8.05MB and it is stopping. I have confirmed it is not a band width issue

Details of Servers

A)Root server is in Mumbai
B)Subserver is in Bangalore.
C)Problem Facing location is Mysore.

Details of Connectivity

A to B 10Mbps MPLS VPN.
B to C 2Mbps P2P.

Who ever is accessing root server from C location(Roaming user)is facing this Problem.

Expecting your support in this regards.