If it is still on a factory config, it will be 192.168.88.1. If you changed it, you need to point your browser to the address that you changed it to. If you changed it to DHCP, whatever device is operating as a DHCP server should be able to tell you what address it is using. If you can't not find it that way, something like WireShark may be able to identify it. Last option is to reset it and it will be 192.168.88.1.
BTW, in my opinion, I have never found the Neighbors list on WinBox to be worth much. I just looked at mine. The Neighbor list is only showing two out of six switches, and one of the two routers. All six Mikrotik switches are on the same LAN and all have Mikrotik discovery Protocol turned on. The one router that is reported is on the same LAN as this PC, and the other is reachable but on a different LAN (the same one as the switches).
RB750Gr3, RB750r2, CRS326-24G-2S (in SwitchOS), CSS326-24G-2S, CSS106-5G-1S, RB260GS
Not sure if I beat them in submission, or they beat me into submission
Warning: I know enough to be dangerous...