We are having an issue with all new enrolled IOS devices. The device is being enrolled correctly, but when we attempt to open self service we get this error. I have verified that we have enough licenses from the VPP. Self service is running properly on our computers just not on IOS devices. 
Solved
ERROR_ALERT_TITLE: ENROLLMENT STATUS FAIL IOS MANAGED DEVICES
Best answer by mtbhuskies
I'm seeing the same issue on 2 ipads that I am trying to enroll. I have removed their record in Jamf Pro, and wiped and restored via Apple Configurator 2, but I am still getting the same error on both ipads.
This was resolved by adding the following into App Configuration tab of Jamf Self Service App in Mobile Device Apps:
<dict>
<key>INVITATION_STRING</key>
<string>$MOBILEDEVICEAPPINVITE</string>
<key>JSS_ID</key>
<string>$JSSID</string>
<key>SERIAL_NUMBER</key>
<string>$SERIALNUMBER</string>
<key>DEVICE_NAME</key>
<string>$DEVICENAME</string>
<key>MAC_ADDRESS</key>
<string>$MACADDRESS</string>
<key>UDID</key>
<string>$UDID</string>
<key>JSS_URL</key>
<string>$JPS_URL</string>
</dict>Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.
