Scheduled sync job fails

English Backup and data protection
1

A single scheduled sync job fails, but if I run the same job manually, it works fine. The destination is another QNAP NAS

In the logs, I can see:

System.log:
6881, 2,2025-12-22,04:51:17,System,—,localhost,[Hybrid Backup Sync] Failed to complete Backup job: “XXY_Backup”. Folder pairs are invalid or inaccessible. Error code: -50, 41,1766375477,A200,Hybrid Backup Sync,C002,Job Status,legacy_qtoken_client_id_admin_0,localhost,Agent,

job_log.csv:
system,5b11ed7e-c204-11f0-84a6-aa27aa27f9b1,error,2025-12-22T04:51:17.2438+01:00,“[Hybrid Backup Sync] Failed to complete Backup job: “XXY_Backup”. Folder pairs are invalid or inaccessible. Error code: -50”

I have tried removing and recreating the sync job, everything works fine on the first manual run, then it fails on the next scheduled run.

Any ideas?

2

If you run it manually a second or third time does the sun job work? And what kind of a sync job? Two way? One way? Active?

3

Looks like it struggles on the second run. It is an Active sync job. The job is stuck at 5% and the log I’ve found in /share/ZFS2_DATA/.@qsync/detail-logs shows the following at the moment:

[2025/12/22 21:21:59] Schedule type: Manually.
[2025/12/22 21:21:59] The deleting extra files option is disabled.
[2025/12/22 21:21:59] The checking data content option is disabled.
[2025/12/22 21:21:59] The detecting sparse files option is disabled.
[2025/12/22 21:21:59] The extended attributes option is disabled.
[2025/12/22 21:21:59] Symbolic link files are included.
[2025/12/22 21:21:59] The detail log is enabled with the maximum size 10 MB.
[2025/12/22 21:21:59] The TCP BBR congestion control option is enabled.
[2025/12/22 21:21:59] Use network adapter qvs0 (10.16.11.103) for outgoing traffic.
[2025/12/22 21:21:59] Maximum retry times: 5; Retry interval in seconds: 180; Connection timeout in seconds: 60; Current retry number: 0.

4

After I’ve cancelled the second run, the third went through without any problems. The log shows no clue whatsoever.

[2025/12/22 21:33:40] Job [NAS_CFG_Backup] started.
[2025/12/22 21:33:40] Synchronize files from a local folder to a remote folder.
[2025/12/22 21:33:40] Server IP address: 192.168.110.101, port number 8899.
[2025/12/22 21:33:40] The SSL connection option is enabled.
[2025/12/22 21:33:40] The ZIP-compression option is disabled.
[2025/12/22 21:33:40] The number of folder pairs = 1.
[2025/12/22 21:33:40] Pair1 = [Backup/NAS, /Backup/NAS/NAS_CFG_Backup/latest/Backup/NAS/].
[2025/12/22 21:33:40] Schedule type: Manually.
[2025/12/22 21:33:40] The deleting extra files option is disabled.
[2025/12/22 21:33:40] The checking data content option is disabled.
[2025/12/22 21:33:40] The detecting sparse files option is disabled.
[2025/12/22 21:33:40] The extended attributes option is disabled.
[2025/12/22 21:33:40] Symbolic link files are included.
[2025/12/22 21:33:40] The detail log is enabled with the maximum size 10 MB.
[2025/12/22 21:33:40] The TCP BBR congestion control option is enabled.
[2025/12/22 21:33:40] Use network adapter qvs0 (10.16.11.103) for outgoing traffic.
[2025/12/22 21:33:40] Maximum retry times: 5; Retry interval in seconds: 180; Connection timeout in seconds: 60; Current retry number: 0.
[2025/12/22 21:33:49] Created snapshot (Backup/NAS) successfully.
[2025/12/22 21:33:51] Finished synchronizing.
[2025/12/22 21:33:51] Sync statistic: Total number of the folders: 5. Total number of the files: 159. Total updated size: 0 byte. Average updating speed: N/A. Time elapsed: 10 seconds
[2025/12/22 21:33:52] Job finished.

5

So is it working now?

6

If I manually run it a few times, it works, but otherwise, it doesn’t. The secondary NAS is offline for 23 hours a day and starts 20 minutes before all the backups begin. All other active sync jobs function correctly, except for this one.

7

When the synchronization fails, could you please verify if the remote NAS is accessible and connected normally?

Additionally, it might be helpful to check the connection status shortly before the scheduled task is set to run. Thank you!

8

It is accessible. I can access it both via web and the ssh.

9

We expect to release a fix in the upcoming version (26.3). Thank you again for helping us improve our product!

10

I have the same problem as amnesia, but my QNAP NAS is a TS-251+ with QTS 5.2.8.3359 firmware and HBS 3 app V26.2.0.938. The destination of the sync jobs is a local CIFS/SMB “WD My Cloud Home” with 4TB (192.168.1.168) and in the same network (192.168.1.X/24) as the NAS TS-251+ (192.168.1.192) .

I have the same error “[Hybrid Backup Sync] Failed to complete Backup job: “Backup_NameXXX”. Folder pairs are invalid or inaccessible. Error code: -50”. Every day; it has always been working fine. If I enter HSB3 app and test the connection or the speed with the WD My Cloud Home new sync job is always working, Then i create a new sync job, then run it manually, and all the other sync jobs works fine. But My TS-251+ shuts down everyday at 22:00 pm and at 08:30 am in the morning starts automatically, and the magic disappears, and it doesn´t work till I create a new sync job in HSB3. All the sync jobs are “One Way” from TS-251+ to the local CIFS/SMB “WD My Cloud Home”.

The local CIFS/SMB “WD My Cloud Home” is accessible before the scheduled task, via web for example. I have only one sync job for day, to avoid any problems.

In the logs of the TS-251+ I can see:

/etc/qsync/logs

[/etc/qsync/logs] # cat qsync-eaede084-f318-11f0-93f6-00089bf2987c.log
[2026/01/17 19:11:39] Job [De_Nas_a_WD_pruebecita] started.
[2026/01/17 19:11:39] Synchronize files from a local folder to a remote folder.
[2026/01/17 19:11:39] Server IP address: 192.168.1.168, port number 0.
[2026/01/17 19:11:39] The SSL connection option is disabled.
[2026/01/17 19:11:39] The number of folder pairs = 1.
[2026/01/17 19:11:39] Pair1 = [homes/admin/pc_ubuntu_trabajo, /mnt/RTRR_CIFS/192.168.1.168/panamawd/panamawd/backup_nas/prueba/enero26/].
[2026/01/17 19:11:39] Schedule type: Manually.
[2026/01/17 19:11:39] The deleting extra files option is disabled.
[2026/01/17 19:11:39] The checking data content option is disabled.
[2026/01/17 19:11:39] The detecting sparse files option is disabled.
[2026/01/17 19:11:39] The extended attributes option is disabled.
[2026/01/17 19:11:39] Symblic link files are excluded.
[2026/01/17 19:11:39] The detail log is enabled with the maximum size 100 MB.
[2026/01/17 19:11:39] Use network adapter br0 (192.168.1.192) for outgoing traffic.
[2026/01/17 19:11:39] Maximum retry times: 5; Retry interval in seconds: 180; Connection timeout in seconds: 60; Current retry number: 0.
[2026/01/17 19:11:40] # WARNING: The second path of the folder pair [homes/admin/pc_ubuntu_trabajo, /mnt/RTRR_CIFS/192.168.1.168/panamawd/panamawd/backup_nas/prueba/enero26/] is invalid or inaccessible, the synchronization will skip this folder pair.

Thanks in advance!

11

And how can I do that, since I don’t have any option to update/upgrade the app, neither in AppCenter nor in the app’s help menu? Are the upgrade options geofenced?

12

I have moved my backup to One-way sync (copy, not mirror) as long as this is not fixed.

13

Same to me. I have the last version of the hbs3 app (V26.2.0.938). I can´t update to hbs3 26.3

Thanks in advance!

14

Hi to all,

Is there any news!?

I don’t have any option to update/upgrade the HBS3 app, so I can’t update to hbs3 26.3.

All my scheduled sync jobs fails every week. Can somebody help me?!

Thanks in advance.

15

Are you sure it is not something on the other side? Do you have fixed IP addresses assigned to everything? Is the other side running out of space? Your version of QTS is not the latest, so that may be why you can’t upgrade to 26.3.

16

If I enter HSB3 app and test the connection or the speed with the WD My Cloud Home new sync job is always working, Then I create a new sync job, then run it manually, and all the other sync jobs works fine. If I don’t create a new sync job, the other sync jobs always fail.

My QTS firmware version is the last I can update for a TS-251+ and has IP fixed 192.168.192. The WD has 2TB of free space and has IP fixed (192.168.1.168). The hbs3 v26.3 app with which version of QTS is related?

Thanks in advance.

17

I’m not sure what you mean when you say if you create a sync job manually then all the other sync jobs work fine. Sync jobs run one at a time (unless you start them one after the other). Do they keep running on schedule then? When do they start to fail?

18

Apologies for the previous slight inaccuracy. I would like to clarify that the issue you reported is scheduled to be fixed in the next version release.

Thank you for your feedback and for your patience!

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