Bought this Mikrotik hEX (RB750Gr3) and powered it up connected on LAN2 to my USB-Ethernet adapter and Macbook. I instantly got IP (192.168.88.X) and was able to browse the webinterface on 88.1. Moved around there and setup a password, saved it and as far as I can remember clicked the logout button to the far upper right. After that I lost my LAN IP number and was assigned a faulty 169. adress. Have tried to reset the router 100 times, using all different kind of reset procedures including the official. When I release the resetbutton after the USR LED starts to blink, the router gives a boot-beep and then nothing has changed. It still gives me 169 adress on all 4 LAN ports. I have changed cable. Rebooted my mac, reset the SMC and NVRAM. Unplugged the USB - Ethernet adaptor, connected my computer to another router (which works fine). I have tried to assign a static .88 adress to no success. The router lights up as it should, the activity LED on the connected port flashes.
EDIT: When connecting internet cable to "Internet" port and still being connected to LAN via port2. I get the public IP of my provider and can use the internet. It seems to be stuck in some bridge mode ? Just tested Router on -> reset 30sec -> router off -> reset 30sec -> router on -> reset 30sec but nothing changes. It is impossible to access router via web interface