iPads (Jamf School) Timeout Before First Connection to ADE Profile

[a_Jamf_Rookie]

Apologies if this is a basic question — I'm new to MDM administration.

During the initial rollout at a new school location, the iPads get stuck after connecting to Wi-Fi and attempt to load the profile. The error message appears to be something like: "Timeout while reaching for profile" (translated from a different language).

Troubleshooting so far:

• I spoke with the Wi-Fi administrator to ensure that the necessary ports are open, and the firewall shouldn't be blocking anything.
• I also tested with a different Wi-Fi network, but that didn't resolve the issue.
• I un- and reassigned the ADE profiles. The profiles are relatively small compared to those at other locations, so size shouldn't be the issue.

Any suggestions for potential solutions or next steps would be greatly appreciated.

[maxhewett]

When you say you tried a different network, did you try a network that is unfiltered? i.e. a personal hotspot? A good tool to use when testing network issues is MEU from AppleSeed for IT. It is most likely to be a network issue, but I'd also check you actually have the profile assigned to the device under Automated Device Enrolment/Placeholders, or that you have the automatic device assignment enabled in the Prestage Enrolment profile.

[a_Jamf_Rookie]

I'm sure it's not a network issue, because now 10% of the Devices got enrolled, simply by retrying lots of times.
Worked both in my clients network, as In our own office. Look on my Updated Post for more info.

[Lasse]

Do you see the device serials listed in the ADE profile in Jamf School? ADE profiles in ASM is one thing, but they only sync once a day usually unless manually triggered('Sync now' in the Dashboard does this).

I would consider to renew the ADE token in Jamf School as well.

Running MEU while on the network in question as mentioned by @maxhewett is a good one to see if any Apple services are blocked on the network.

[a_Jamf_Rookie]

The device srial numbers are shown in the ADE profil. Please look on my Updated Post for more info.

[a_Jamf_Rookie]

Update: Some device got through the timeout and now show up in the Devices>Inventory, but only 10%. Weirdly this happened both in or Clients network as well as in our own office (Which does not block ports). The Devices were enrolled by a third party (because not a certified reseller withot reseller-ID) via Apple Configurator 2. Maybe thats an issue? But they do show up ADE? Its very strange.

[Lasse]

But they show up in ASM and is assigned to an MDM?

Apple Configurator can be used to add a device in ASM/ADE. But if you log back in with Apple Configurator for Mac, you can take over VPP or ADE tokens. This may make your ADE workflow fail between ASM and MDM. I would try, if possible, to use Apple Configurator for iPhone and remove one device from organization in ASM, and add it back in. If that goes through without issues, if might point to the Apple Configurator for Mac workflow is flawed for your needs. You might have to remove the other devices from the organization and re-enroll them with Apple Configurator for iPhone.

[a_Jamf_Rookie]

Yes, they do show up in ASM. 
However we found a workaround that allowed us to finally enroll the iPads. The devices were enrolled via Apple Configurator 2 but to our (and not the schools) location. It was tried out of deperation, but it worked. Then the devices were manually reassigned to the school location. This worked fine, until the devices were reset. The devices are only loading the smart devicegrups but not the static ones. They also dont show the devices Names on the Lookscreen. If then assigned the static device groups over Inventory > Add device Group, the name and configured Lockscreen reappears. So it seems to be an Profil issue with loading from ADE? 
To add to the confusion, if I reset the device a second time (with installing MDM Profil after erasure) it straight up goes missing from inventory. Even though some Apps are loaded from Jamf on the activated IPad. Custom Lockscreen with Name is missing, but device Name in Apple Info > Name is correct.
I've contacted Jamf Support now.

[a_Jamf_Rookie]

Sorry I forgot some details
They do show up in ASM and are assigned to our MDM Server. Both Tokens were also renewed and a Second ADE Profil was set up were 1 Devices got assigend for testing. That is the device described in the last paragraph.