it's the exact same setup. I just took out a 50' and put in a 100' and moved them further away. so I'm thinking, MAYBE damage to the 100 foot cable?
I have a rocket hub coming form my cell phone company, as I'm on weak internet on a farm, that I will be installing above my miner's so they will have their own dedicated link.
I just hope a bunch of miner's don't each much for data
Could be damage to the 100' cable but it's weird that 3 work fine.. If you switch the cables around on the switch does it make a difference on which devices work? Maybe a few of the switch ports got zapped or pins bent or something? Is the switch gigabit or 10/100 and what's your router ports speed? The miners should not use much bandwidth for data, so I wouldn't worry about that.