I had similar problems. My Mach2 was connected via a wired Ethernet connection but ultimately needed to pass through a series of managed LAN switches. My hypothesis is that, when the switches are heavy with traffic, the time it takes to get the signal through all of the switches exceeds the response time the CP4 or CP5 is looking for. My setup was CP5->Switch1->Switch2->Switch-3->MainSwitch->Router. Most of the switch connections are fiber; only one is Cat6.
I simplified the LAN setup
- Removed one switch from the daisy chain
- Reduced the security-camera traffic going through those switches
At some point I will investigate setting switch port priorities that favor the CP4/5 links but I need to read up on that first since I am currently using jumbo frames and my switches (TrendNet TPE series) won't let you do that with jumbo frames.
Since then I haven't seen the issue nearly as much, if at all. I also added a USB backup connection which seems to work well.