I have had this issue since day one about 2 years ago.
I am using the most up to date version of the plugin. I have had indigo installed on 2 diiferent computers, and I have tried it both using the global cache IP to Serial and directly via ethernet. Nothing solves this issue.
I have 3 Denon AVRs. 2 of them are AVR-X4000 and one is an AVR-3313CI. All have the same problem with this plugin.
It used to be that if I use Indigo to do any action on one of the receivers, it will stop responding for a few minutes and then come back to life.
Now it is worse. No command works on any of the receivers. Volume, power, etc.
Furthermore, to complicate things, the device status shows connected, but ALWAYS disconnects and shows unavailable after being connected for a few hours. Keep alive is enabled. Only way to get the connections restored is by restarting the plugin.
But anyway, the whole thing just doesn't work for me at all.
Any ideas? I am thinking maybe something in my router. I am using a DD-WRT router.