I am experiencing the same issue. I haven't found any documentation from Apple or guides on any blogs about how to supervise and enroll existing devices which are not in the DEP.
I have noticed that when you fill out your hostname in the mdm server URL field, it fills in /devicemanagement/api/device/dep_mdm_enroll
sometimes. This makes me suspect that it only works with DEP enrolled devices, but I haven't found any information confirming or denying that. I did look at the Profile Manager logs in OSX server and it's giving 401 unauthorized errors:
1:: [13961] [2016/04/26 16:20:12.755] <192.168.244.8> >>> Processing POST dep_mdm_enroll
1:: [13961] [2016/04/26 16:20:12.759] signerIndex = 0, signStatus = 1
0:: [13961] [2016/04/26 16:20:12.794] <192.168.244.8> EXCEPTION: 401 Unauthorized - Requesting user digest authentication at
#0 /Applications/Server.app/Contents/ServerRoot/usr/share/devicemgr/backend/php/dep_mdm_enroll.php(173): DieUnauthorized('Requesting user...')
#1 /Applications/Server.app/Contents/ServerRoot/usr/share/devicemgr/backend/php/dep_mdm_enroll.php(201): _request_authorization('a7742da74c462b5...')
#2 {main}
1:: [13961] [2016/04/26 16:20:12.794] <192.168.244.8> <<< Sent Final Output (55 bytes) - POST dep_mdm_enroll
0:: [13961] [2016/04/26 16:20:12.794] <192.168.244.8> Completed in 43ms | 401 Unauthorized [https://<hostname>/devicemanagement/api/device/dep_mdm_enroll]
Has anyone had any luck getting this to work?
I have a supervision identity defined and I'm able to supervise devices with Apple Configurator 2. I can manually enroll them into the profile manager MDM by browsing to https://hostname.domain/mydevices on the device and pushing enroll, but when I try to do the enrollment with Apple Configurator, it prompts for the username and password from the device on first boot. When giving good credentials at this step, the device server log is showing the errors I mentioned above. I have a case open with Apple enterprise support to resolve this and they've admitted I have a good setup and escalated my case to a senior advisor and now to engineering. I think it's a bug.
I also watched the iPhone log with Xcode and according to the device it can't reach the MDM server, even though the events are showing up in the logs on the MDM server. We are certain it is not a networking problem. The senior apple advisor said he encountered another client with the same issue just yesterday.
Anyone have any luck with this? Having the same issue that the iPad is asking for a username and password when I try to enrol from the setup screen. If I enter the local credentials used on the on the mac for profile manager, it installs the profile. I want to avoid that.
If I supervise the ipad, set it up (without enrolment) and then push the enrolment profiles to the iPad after setup it doesn't ask for any credentials.