What is the problem?
1.5.1 Error: No more candidates to test, and no working port/baudrate combination detected
I had this problem with the last 1.4 release but changing the usb port worked before.
What did you already try to solve it?
Restarted the printer, changed the cable, restarted the Pi, updated the pi firmware
Have you tried running in safe mode and if so did it solve the issue?
serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support! Not log excerpts, complete logs.)
Additional information about your setup
OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
Ender 3, Raspberry Pi 3, windows, google chrome