Configurator failed to add iPhone, unable to join Wi-Fi network NSError: 0xbe6b0d540

I'm trying to add a company iPhone (XR) into ABM using the Configurator app on a second iPhone (13), the latter of which is connected to our office Wi-Fi.

When stopping at the Choose a Wi-Fi Network screen on the target iPhone, the circle of blue dots appears, and I can scan as per normal, but then the below error appears on the target iPhone.

I've used the "Erase iPhone to try again" option and done so with the same result.

I've tried pairing manually with the same result.

On the third atempt, I saw the target iPhone attempting to join the office Wi-Fi (not the first one on the list, uses a device certificate to join) before failing with the error.

After starting again, I joined it to a different Wi-Fi, then erased the iPhone and started again (again).

I wasn't expecting this to work, and so I was unsurprised when it tried to connect to the office Wi-Fi and gave the same error.

I've previously been able to add a MacBook into ABM using Configurator on this (second) iPhone.

I'm logged into Configurator with my ABM account and have a default MDM Server defined.

The Device Status list in Configurator now shows four entries for this iPhone XR, all with the green & white tick symbol, but when searching in ABM Devices it is still not found.

Any suggestions greatly appreciated.

Failed to Add iPhone

NSError: 0xbe6b0d540

US Desc:

Desc: Unable to join Wi-Fi network

Code: 0x37 (55)

...Underlying error:

NSError: 0x6fe90c130

Desc: The operation couldn't be completed. (com.apple.corewifi.error.wifid error -100.)

Domain: com.apple.corewifi.error.wifid

Code: 0xFFFFFFFFFFFFFF9C (-100) [sys = 0x3F, sub = 0xFFF, code = 0x3F9C (16284)]