What is the problem?
With options on Serial Port and Baud Rate set to Auto. I tried to connect to Octopi, but got the following terminal comments;
- Changing monitoring state from "Offline" to "Detecting serial port"
- Serial port list: 
- Changing monitoring state from "Detecting serial port" to "Error: Failed to autodetect serial port, please set it manually."
What did you already try to solve it?
I looked in the drop-down menus for Serial Port, but "Auto" was the only option.
I then went to settings/serial connections and looked in the options there, but again there was only "Auto". However, there was a window in which I could enter other ports, and I entered "COM6" and "COM4", which I know to be serial ports through which I can connect my computer with my printer (both of which appeared to be working).
I tried again with these new ports entered, but I got the same error messages.
I saw some advice on how to enter additional ports, but I didn't understand the advice at all.
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware,
serial.log or output on terminal tab, ...)
I had not used Octoprint since late last year, and I found that I should update, since there were Messages telling me so.
I upgraded first from 1.3.6 to 1.3.8 (I think!) , even though I know now I need not have bothered. Could something have gone wrong here? It was only after the update that I attempted to connect.
My printer is a Prusa i3, with Marlin firmware