Changing A-B IP Adresses

[AlwaysLearning 0]

Hi. I was recently tasked with changing the IP addresses on 3 ControlLogix, 1 SLC 5/505, and 1 HMI computer(InTouch) on a working system. Everything seemed to go reasonably well (all devices are pingable from the HMI box, the system mostly works, InTouch responds as expected, etc.). However, there are several (all) MSG blocks in the SLC that are now setting the .ERR bit after changing the IP address under the multi-hop tab. None of the PLC's have been power-cycled, but all have been stopped/started. All devices are also pingable from a troubleshooting laptop. Monitoring the .ERR bit with Rockwell's OPC Test Client is what is what is showing me data changes. The IP addresses were changed from a private range to a public range. All devices are connected to the same (unmanaged?) 3Com switch. Again, this system worked prior to the IP changes. Is there any history with MSG block failures after IP changes? Is power-cycling a no-brainer? Any trobleshooting tips/procedures? I'm pretty confident that I've discovered all of the MSG blocks and communication paths in the system, but next steps for troubleshooting are escaping me. Thanks in advance.