[exim] message_size_limit error

I have this rule

message_size_limit = 15M in my configure file

But if i try to send an email with an atachment 11,7 MB


I have this error


2007-01-18 13:50:41 1H7WiD-000075-Em rejected f (parasit) [130.206.126.138]:
message too big: read=16167122 max=15728640