Outlook Express and wireless connections

Hello,

I use to have a wireless connection of 11Mbs, but now I have installed a new
router a 56Mbs one, and connected that last one with the first one, who is
now being used as a ethernet modem.

I have a wireless connection to both of the routers and both of them give me
an internet connection. But with the new one, I'm unable to send e-mails with
outlook express. First I tought there was a problem with uploading, but it
isn't that. The 56Mbs router is one from Trendnet.

Does anyone has a idea how to solve this problem?

Thanks