I've now had several MikroTik devices I couldn't connect to using Winbox and MikroTik MAC address. It doesn't even find it in the neighbors. If I plug my computer to a switch (ie. Cisco) and the MikroTik to the same switch (in the same VLAN) I can see my MikroTik device in the neighbors and I can normally connect to it.
It doesn't happen always and if I use a different computer I can connect to MikroTik just fine.
Any ideas where to start looking? It is obviously a problem with my PC but I don't know what could be the cause.