About a week ago, all of the devices in the Indigo Touch app became red and said "- interface error -". Then I noticed that the nothing was working via Homekit either (using Homebridge) so I went to Indigo (6) and saw that it wasn't seeing the PowerLinc (2413U). The PowerLinc and Indigo had be working great for about 4 years. I noticed that there was no status like on the PowerLinc so after trying to reset it, plug it into different outlets, etc, I concluded that it may have just died.
This evening I connected a new 2413U and Indigo is saying the same thing - "INSTEON interface (PowerLinc 2414U/2412U/2412S/2413U/2413S) is not connected or online. Check your interface type and connection, then choose Enable from the Interface menu." On the Interface screen in Indigo, the correct type is selected and it doesn't seem to have any issue with the serial port selected (of which there is only one option). Yet, the Interface indication at the bottom left of the Indigo window is red with a line through it (PowerLinc Modem).
After some additional digging here online, I found what to look for to see if the 2413U was being seen by the computer and it is. I do see "FT232R USB UART" listed in the system report under USB.
When I launch Indigo, I get the message "Failed to establish connection or open serial port to interface. Make sure the correct interface type and port are chosen in the Preferences dialog and that the serial device or adapter are plugged in correctly."
So now what should I try?