Endpoint manager and Digium phones

I’m trying to get my d50’s to be configured by endpoint manager.
I have option 66 setup to give the tftp server address. It’s working on my grandstream phones but not on my d50’s.

When the phone boots up i get a "communications error"
Error fetching configuration. You can retry or chose a new server.

I assigned the line, template and model from the network scan of endpoint manager.

Is there a special way to use endpoint manager with the digium phones?

Digium does not support tftp. Only FTP or HTTP