How do I solve error Blue/Red/Red/Blue on P30X Slaves ?

Hello, I have a chain of P30X Stations, 5 slaves connected to one Master. The network is connected to a remote Backend.I had to change the backend address, After the Change in the network IP, Two of the Slaves showed the error "Blue/Red/Red/Blue" The Master Web-interface showed the two slaves as Degraded, IP/ Mac address where correct, the slaves connected to the new ip address. Previously they where working fine, the DIP settings are correct Pin 2.5 "on" the rest "off". Later, All the remaining 3 Slaves went into the same state Blue/Red/Red/Blue, The Master Web-interface is now showing all slaves as Degraded. The MAC/ IP address are correct.Replacing the Master didn't solve the issue. I did a Firmware update to the Slaves, also without success. When I restart the slaves, it immediately shows error in the front, it doesn't show what address the station is connected to, and the Firmware version. it looks like they're in a bricked state, after the network IP changed. To ensure the connectivity issue isn't on our backend, I Activated on the Master the local DHCP server and disconnected the Backend, it didn't solve the issue, the Web-interface showed all the slaves new MAC/ IP address, so I can conclude the error is not in our backend, I spoke with Keba support, they're not helpful. I was hoping I could get some support here before I replace all the Slave boxes, I'm having the impression I need to wipe clean the memory of the Slave Stations, or do some form of deep factory reset. I'm Working in Germany, all Station are "Eichrecht Konform".Thank you very much.