Hello, I have a Mikrotik LHG 5 and after doing a reset, the winbox does not recognize it. What I can do?

Are you able to give us a little more information on what you mean by recognise?
Are you able to tell us if the networking device or PC recognised a layer one connection, on a mikrotik device the interface will say running or if you are connecting this directly to a PC in your network status tab it should indicate that a cable is plugged?
If this is not the cause I would check on the device to make sure the power light is on etc.

If you are able to get a layer 1 connection I would suggest typing in the mac address of the ethernet port into inbox and see if it is able to connect, if you are connecting through a mikrotik device I would first make sure that the port to the LHG and the PC are bridged together and if they already are I would check the bridge>hosts table to see if there is 2 devices at least reported one for the interface going to the LHG 1 and should have DL next to it and the other will be for the LHG its self and it will say D
If you do not see this try another port and cable and see if that helps.

report back what you find and we can help further troubleshoot from there