message problem

[<looper@bluecocoa.co.uk>]

I am baffled if I send a message from my webmail account it seems to get
to the loopersdelight list, however sending a message from the Mail
program of OSX to the list using the same account, my messages don't
seem to be getting through at all although the program says have been
sent to Loopers-Delight@loopers-delight.com  successfully.
Anyone have any suggestions?
As i really don't want to use this webmail site for looking at the
loopers list as its slow and cumbersome.
The messages are downloaded successfully and are sent successfully from
Mail in OSX 10.3.6 but don't seem to be coming up on the list. ARGGHH!
any advice greatfully recieved.
geoff