Do you know the user/password to login?
If not, there is no way (at least we all hope so 
. Except doing a factory reset (netinstall) losing everthing.
If you have user/pw, you can use serial terminal to access the device and view/export config. RJ45 serial cables are cheap and avaialble everywhere.
The serial port is exactly for such cases were the device is not accessible on network ports. And that’s also why RJ45 console cable is part of the basic toolkit of every network technician.
(except that you need multiple adaptors, because various network equipment vendors use diferent pinouts)
FWIW, the serial port will ask for the username/password too. winbox can work in Layer-2 mode so if you know the MAC address of the port (should be a sticker on bottom of router with them), but again you needed the right password.
Otherwise if you don’t have the user+password, and if SNMP was enabled on the router, you might be able to deduce some/most of the configuration from walking the SNMP (if previous enabled that is).
While MikroTik is using the Cisco pinout which is by far the most common among vendors. But yes, there are others.