Trackback not working, after migration to a new server.

Hi.

In my portal I have installed trackback module, and previously it worked fine, and accepted trackbacks both from blogs hosted locally, and blogs from other platforms. But after we had migrated to a new VPS, the Trackback only accepts the trackbacks from other webpages, and simply does not recive or even send trackbacks to content hosted on our portal. What possibly went wrong?