DS-KV6113-WPE1 Platform Access Can't Enable

[Jami3]

I installed DS-KV6113-WPE1 today and updated the firmware to the latest version.

When trying to enable platform access, the Enable button is disabled and I cannot enable it whatsoever.

Is there something I am failing to do?

Firmware Version: V2.1.5 build 200904
The doorbell is hardwired ethernet - into a POE switch which goes directly into router.
I have tried turning DHCP on, although it is now turned back on again.
DNS Servers are set correctly. 8.8.8.8 and 8.8.4.4.
I have it recording on my NVR successfully too.

 

[Jami3]

As per the advice Hik support gave me when I had a similar hik-connect problem with my NVR, the solution is to restore the device.

This sorted the problem.