ok, first mistake is that it is from 0 to 255 thus the up to 256 so you may have to do a form of factory reset. I admit lack of knowledge how to do it, usually pressing and holding anything looking like reset and power button while it's unplugged from the wall for a count to 60 out loud does it. Sounds stupid counting out loud, but it's to ensure you are draining every bit of power from anyting that may be storing the IP address.
For next time, try starting at 200 and counting up for your mining rigs as example 192.168.1.200 for the first. Since you did say the others are working fine, leave the Cubes as is, disconnect one of the blades ( either of them ) and see if you can connect to the default as they may both be asking for the same IP address.
The best way to deal with this kind of situation is treat it like a cheap Lynksys ( clone of LinkSys ) router and know how software wise to beat it with a stick until it does what you want!
