When accessing the Migration Phone Service (on the phone) you may see a message 'Currently unable to identify this device' for a brief period of time, however the page does refresh automatically and should proceed to the normal migration options.
This message effectively means that the device (requesting phone) is not currently listed in the device list within MigrationFX, you can check this in the 'Phones' page of that AutomationFX admin interface (i.e. http://127.0.0.1:8181 from the machine AutomationFX is installed on).
AutomationFX periodically synchronises the device information in CUCM, technically there are 2 synchronisation steps:
1. Cluster Update - a full list of devices (30 minutes by default)
2. Cluster Refresh - changes since last refresh (1 minute by default)
The 'Cluster Refresh' will pick-up devices that have been edited in CUCM as well as new devices (i.e. auto registered) within a minute of that change, until that device in synchronised from CUCM to AutomationFX the Migration service will not be able to identify the device.
If there is a device in CUCM but not in AutomationFX it is typically due to licensing, for example if there are 100 devices in CUCM, but you have the MigrationFX Lab license that permits 50 devices, only the first 50 devices will be synchronised to AutomationFX. You can specify up to 5 devices (MAC Addresses) as part of the MigrationFX Lab license, this is an option when first obtaining the lab license, however if you need to change/add trial MAC Addresses you can send them to firstname.lastname@example.org and we shall add them.
So as long as the phone count is greater than the number of devices in CUCM, or if you have specified one or more trial phone MAC Addresses they will always be available and you should not see the 'Currently unable to identify this device' message.
Note: When specifying Trial Phone MAC Addresses please ensure to include old and new devices even if they have not yet been added to the cluster. When AutomationFX synchronises if it sees a new device and that device MAC address is part of the trial list it will still be imported/synchronised with CUCM even if the phone count is exceeded, hence you can use the Lab license to test with a production system.