mail problem

[nalsdixit]

having a problem with sending some attachments. msg pops up saying file is bigger than 1,000,000b and therefore cannot be sent. the file then sits in the outbox until i manually delete it.

however i cannot find anyway to increase the allowed file size anywhere in mail or system preferences. checked with isp who says there is no restriction on file size from their side

any ideas how to resolve ?

tks