I've had issues like this with iOS devices in the past. I'm not familiar with the iOS network stack, but suspect that iOS devices maintain some kind of internal list of recent DHCP leases and seem to think that leases are still bound when they are not. It could be that your Microsoft DHCP server wor...

Briliant to hear about all you're doing as a company to help with comms etc in Ukraine...bravo!

It's not clear from the OP whether the router has been set up and connected to the internet for some time, or whether it's straight out of the box & the OP is setting up for first time. If the latter, you can just reset the router to factory defaults and log in using 192.168.88.1, admin/no passw...