Unifi AP - IP address changed

Hi all,

Have a UAP AC LR device... and it's still doing its AP job just fine. However I wanted to setup some controls on it so the kids would get booted off at bed time. When I went into the web Unifi management tool it shows the AP as disconnected. The IP address listed is not the IP address I see allocated to it in our modem/router's LAN management page. The IP address Unifi thinks it is at cannot be pinged. The address the router says is a ubnt device does answer ping.

Has the AP gone and got itself a new DHCP address? The Unifi management page doesn't seem to know about that. I tried to manually edit into the AP the new address as a static IP for the AP but it doesn't seem to have updated to it and still shows the old address.

Is there a proper way I should deal with this? I think I should allocate a static IP address outside the routers DHCP range and set that up on the AP. I'm kinda blundering around trying stuff at the moment without any success.

TIA

JohnO