Cannot Connect to Ender 3 with Octoprint

#1

What is the problem?
I followed the directions exactly on how to use Octoprint on Windows 10: Setting up OctoPrint on Windows

and once I am logged in, I cannot connect to Ender 3. Terminal says "Trying COM13" even though I have specified COM16 in serial ports. Refreshing Connection does nothing.

What did you already try to solve it?
Searched google, read other help topics that ended up being unrelated, made sure in Device manager that printer was actually connected to COM16 (COM13 is reserved for wireless mouse I am using).

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)

Octoprint version 1.3.10, Creality Ender 3, Marlin 1.1.9. Octoprint.log and Serial.log have nothing about connecting to printer as far as I can tell. Serial.log only has "Enabled serial logging" message after I turned it on.