I am not sure if this was happening before I upgraded from 7.9.6
It’s being closed by the device.
Do you have any tags subscribed, and if so, at what rate?
About 100 tags at 10 second scan rate.
Hmm. Maybe try 1 tag at 5 seconds or something. Most Modbus devices will close a connection after ~10 seconds of inactivity, you might be losing the race.