Setting up WAP 561 on UTM 9, not assigning IP

We have a UTM 9 firewall running and several WAP561 devices repeating the wireless throughout the office. Everything works fine with the existing 3 WAP561 devices we have running.

When I plug in a new WAP561 device and add it to an existing cluster (single point setup) it copies all the information from the cluster successfully. (except it is using a different host name on a different IP of course). I can login to the new WAP Wifi through PEAP to the corporate network as well as the guest network but neither of them are assigning an IP, so the internet is not working.

I can't think what I missed. The working WAP561 and the non-functioning WAP561 have the same firmware version too. It's like the firewall is blocking it.

I've added the new device as a Radius Client fyi.

Is there any extra step I missed to tell the firewall that this WAP is authorized to repeat the wifi or anything like that? I'm new to this type of setup but I've Googled for days before asking the question.

I can't get any of these 3 WAP561 devices to work that we have spare. I'm wondering if they are all fried? I'm new to the company so I don't know the history of the spare WAP561 devices but I believe they were working and removed from an office extension that was closed down.

I can't see anything meaningful in the WAP logs and there's nothing showing up on the firewall log on the UTM 9 (like request denied etc)

I feel like it should just be working but I have no previous experience of these devices to base it on.

Please someone help if they have any suggestions.