I've been searching and searching, with very little good answers, the question I'm asking is, is it at all, possible to do a MITM attack on 802.1x?

All my own attempts when using a radius server have ended the same way, no poisoned client can get to the internet or anything like that, secondly if it's possible, would it be possible to do MITM on a network with 802.1x where the attacker haven't authenticated?