Cannot access HAPax3 wireless config html/webpage

I have a UB5009 router (192.168.88.1), - no special set up, supplied with fibre. I have a functioning wifi mesh setup (linksys). Address range from the UB5009 is 192.168.88.10 - 192.168.88.254.
I want to try the HAP ax3 to see if it will replace or augment my linksys mesh.

I have connected the ax3 to a port on the UB5009. Over ethernet it is on 192.168.88.249 , I can ping it.
On wireless it is Mikrotik_CBD205 , and I can connect to the wifi channel using the password on the pullout drawer.

As my UB5009 has the IP 192.168.88.1 the wireless ax3 seems to have adopted 192.168.88.249

I cannot connect using the MAC address and winbox.
I cannot open http://192.168.88.249 (even though I can open other devices on my network, - so I don’t think it is a browser issue).

By default, device considers ether1 to be WAN port and management is not possible via that port. Management is possible via all other ports (including wireless). However: by default it also serves as router and its LAN address is 192.168.88.1/24 … which conflicts with your existing LAN.

The best way out of it is to use winbox to connect (again through any of ports except ether1) by clicking MAC address, shown in table with discovered devices. Then reconfigure hAP ax3. If you want to use it as AP only, then minimum would be:

  1. disable DHCP client, bound to ether1
  2. disable DHCP server, bound to bridge interface
  3. set IP address on bridge interface to something other than 192.168.88.1 … e.g. set it to 192.168.88.2/24 (if that address is free). Also add default route via your main router (necessary only for upgrades).
    Alternatively you can go with DHCP client, bound to bridge interface. I don’t recommend dynamic addresses on network infrastructure (if DHCP server is not available when device needs to obtain or renew address, it may renain address-less or it may have some random address, in either case management becomes tricky).
  4. remove ether1 from interface list named WAN
  5. add ether1 to default bridge as port
  6. connect ether1 to your LAN and verify that device is now accessible through LAN (including management)

After this point there’s a lot of redundant setup (e.g. most if not complete firewall part, DHCP server settings, etc.). It should not interfere, but I’d remove it never the less.

Reset to caps mode is probably easier. Isn’t it?