Dec 24, 2019 10:51:34.454 [0x7f5393d11700] DEBUG - Media Server: Tested all servers in 1.5 seconds.
Dec 24, 2019 10:51:35.300 [0x7f5393fff700] DEBUG - Grabber: Cleaning up orphaned grabs.
Dec 24, 2019 10:51:35.368 [0x7f5393fff700] ERROR - Couldn't check for the existence of file "/volume2/FILMY/.grab": boost::filesystem::status: Permission denied: "/volume2/FILMY/.grab"
Dec 24, 2019 10:51:35.369 [0x7f5393fff700] ERROR - Couldn't check for the existence of file "/volume1/FOTKY/.grab": boost::filesystem::status: Permission denied: "/volume1/FOTKY/.grab"
Dec 24, 2019 10:51:35.370 [0x7f5393fff700] ERROR - Couldn't check for the existence of file "/volume2/HUDBA/.grab": boost::filesystem::status: Permission denied: "/volume2/HUDBA/.grab"
Dec 24, 2019 10:51:35.372 [0x7f5393fff700] ERROR - Couldn't check for the existence of file "/volume2/ROZPRAVKY/.grab": boost::filesystem::status: Permission denied: "/volume2/ROZPRAVKY/.grab"
Dec 24, 2019 10:51:35.373 [0x7f5393fff700] ERROR - Couldn't check for the existence of file "/volume2/SERIALY/.grab": boost::filesystem::status: Permission denied: "/volume2/SERIALY/.grab"
Dec 24, 2019 10:51:35.373 [0x7f5393fff700] DEBUG - Grabber: Cleaned up 0 decrepit directories in 0.0 sec.
Shows me plex cannot read your media shares on /volume1 and /volume2
If you previously had an older version, this might explain it.