What is the problem? In Octoprint clicking Connect button simply recycles the printer, and printer LCD screen displays 'Reading SD card'. then goes back to Prusa's Home screen, if SD card inserted in printer. Simply recycles printer's Home screen if SD card removed.
WRITE HERE Tried Firefox & Chrome. Tried Serial Ports: AUTO, /dev/ttyACM0 and /dev/ttyACA0
WRITE HERE yes
WRITE HERE no
You can download this in OctoPrint's System Information dialog ... no bundle, no support!)
OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
WRITE HERE OctoPrint 1.8.7 (and previous); Python 3.7.3; OctoPi 0.18.0 (and previous). Pi 3B+, Prusa MK3s w/ MMU2s (not configed yet), FW Win 10 64