Can you further describe the azure dialog box? as this isn't consistent with the expected operation of DHCP and is either an address conflict as suggested by SD or the function of some third party s/w.
Just to be clear (using OS X in case that wasn't) a typically 'Apple' styled info box pops up in the middle of the screen telling me that my address has been changed and that I'm no longer connected, and I either press the white cancel/decline button OR the azure blue accept/change button to continue online. My curiosity is why, why has another device priority over another seemingly and why couldn't the router just leave me alone and give one of the other addresses to the other device(s) allowed on the network ?
When I am referring to my address changing it's NOT the Mac address, but the IPv4 address if that helps
SHJ