Endpoint Manager - Yealink T46G provisioning - PJSIP no go

Unless EPM isn't correctly setting some odd setting burried way in the config I can't imagine why it wouldn't provision. Have you checked that the password is correct in the file that it is provisioning from? That's the only parameter that you can't confirm in the phone gui.
I would try hand making a file with the template off of the yealinks website with just your login credentials and see if provisioning from that file works.