IoT gateway, periodic disconnections with "BadTimeOut" errors

DSRTM

Hi Everyone, we have a IRB6700, IRC5 with PC SDK and IoT gateway 1582-1, using RW 6.13.

We've installed Aveva Edge through a switch to the IRC5, using IoT gateway 1.2.1.  Our IT expert has got the security certs sorted, in a non-traditional manner, generating a server cert through a 3rd party software instead of installing the LDS.  We're only 1 robot on a dedicated network to it's own PC, and the documentation states the LDS isn't needed anyway.  

We can connect and generate tag links to the OPC UA however it is not reliable and aveva reports the following errors after several hours of running normally:

-The monitoring of the connection to the server indicated a potential connection problem.
-Failed writing on server "BadTimeOut" Error 0x800A0000 

There's generally nothing before these errors listed to indicate something has or is happening.  This is also with the HMI idle, just sitting connected and watching a heartbeat (poll rate is 500 ms, so nothing too taxing).

I realize there's a lot going on with this network, but i'm hoping this error points to something that someone may know about.

alternatively, I'll need an OPC UA support person, if someone can direct me.  ABB Canada knows nothing.

quick edit - this is an error that the client is throwing, so its possible it's a client(aveva edge) and IoT gateway issue.... or client only thing.  I need to start somewhere in my search. 

thanks all.