I was having the same (and other) issues with the 16HDs and after finally getting my issue escalated by involving where I bought them from I got some info...
The Prime 16HDs cannot be managed via the website, that's why the SN can't be entered. Since they don't have WiFi and work off BLE... Seems they extended these SNs to address that.
I had issues with loading presets, the videos didn't help, they are all for the older lights and that option wasn't there. So on my android I had to download an AIP file, and then select Open With > MyAI and that imported it.
Lastly, we discussed the lack of WiFi and control-ability... not being able to use the website, Apex, etc... and he said they actually do have WiFi, that it is disabled and will be unlocked at a later date.