When recovering the NAS, did you run file system checks ?
This error is telling me that PMS thinks it has the data files but nothing is actually there.
This type of error only occurs when there is major corruption of / damage to the file system where it is installed.
Oct 21, 2020 06:03:13.433 [0xebd11b90] DEBUG - Request: [127.0.0.1:54474 (Loopback)] GET / (6 live) GZIP
Oct 21, 2020 06:03:13.440 [0xf1bffb90] DEBUG - Completed: [127.0.0.1:54474] 200 GET / (6 live) GZIP 8ms 1178 bytes
Oct 21, 2020 06:03:13.605 [0xeefffb90] ERROR - SQLITE3:0x8e4ec44, 14, cannot open file at line 34876 of [fc49f556e4]
Oct 21, 2020 06:03:13.605 [0xeefffb90] ERROR - SQLITE3:0x8e4ec44, 14, os_unix.c:34876: (2) open(/share/HDD_DATA/.qpkg/PlexMediaServer/Library/Plex Media Server/Cache/gn_lists.gdb) - No such file or directory
Oct 21, 2020 06:03:13.611 [0xeefffb90] ERROR - SQLITE3:0x8e4ec44, 14, cannot open file at line 34876 of [fc49f556e4]
Oct 21, 2020 06:03:13.612 [0xeefffb90] ERROR - SQLITE3:0x8e4ec44, 14, os_unix.c:34876: (2) open(/share/HDD_DATA/.qpkg/PlexMediaServer/Library/Plex Media Server/Cache/gn_lists.gdb) - No such file or directory
Oct 21, 2020 06:03:13.618 [0xeefffb90] ERROR - SQLITE3:0x8e4ec44, 14, cannot open file at line 34876 of [fc49f556e4]
Oct 21, 2020 06:03:13.618 [0xeefffb90] ERROR - SQLITE3:0x8e4ec44, 14, os_unix.c:34876: (2) open(/share/HDD_DATA/.qpkg/PlexMediaServer/Library/Plex Media Server/Cache/gn_lists.gdb) - No such file or directory
You also should be advised: Version 1.9.6 is MUCH TOO OLD to use now. The minimum is 1.15.2
Oct 21, 2020 06:02:55.290 [0xf3111b90] INFO - Plex Media Server v1.9.6.4429-23901a099 - debian PC i686 - build: linux-debian-i686 qnap - GMT 01:00
Oct 21, 2020 06:02:55.291 [0xf3111b90] INFO - Linux version: 3.4.6 (#1 SMP Fri Aug 21 10:45:45 CST 2020), language: en-US
Oct 21, 2020 06:02:55.291 [0xf3111b90] INFO - Processor Intel(R) Atom(TM) CPU D510 @ 1.66GHz
Lastly, be advised this processor isn’t supported either. It does not have enough CPU speed to run correctly.
If you are not able to use QTS 4.3 or higher then the recommendation is to allow the QNAP to be what it is best at – a NAS – and setup PMS on a more capable computer.