Echo expansion bridge issue

I'm having a problem with losing access to my Echo controller via the expansion bridge and iOS app.  There are times when the app just doesn't see the expansion bridge.  The switch that the expansion bridge is plugged into continues to show connection, but both wireless and wired connections aren't connecting with the expansion bridge.  Then, I can try again 5 minutes later and everything works just fine.

My Echo controller has been installed for less than a year.  This current issue with losing connection to the expansion bridge has been going on for less than a month.  At least, it was about that long ago when we first noticed this issue.  Before then, the iOS app always connected without issue.

I am currently using a dedicated, manually configured network with no other devices connected.  Just the expansion bridge, a gigabit switch, and a wi-fi access point.  I will connect my iOS devices both via wi-fi and connected directly to the switch via a lightning to ethernet adapter.  Either way, I'm having this connection problem.

I don't suspect the switch because I still had the problem when I hard connected between the iPad with ethernet adapter and the expansion bridge.  Mostly it worked, sometimes it didn't.

The expansion bridge:




Anyone have any ideas regarding this?