contact form issue - 404 error

hello

when I use the contact form
which appears very
then after I sends an error message 404
(i fix 404 with make contact redirect to home page)

the sender gets a good copy
but the contact does not receive the message

Contact the box works well in pop and smtp

thank s for help

Could you check whether the same happen on default Joomla! template like Beez? It looks like redirect after sending mail provide to some page which not exists but it should redirect your to the same page and shows only message that mail was sent.