Backup Job Fails with "timeout while getting the remote" - but Remote is Reachable

[music9050]

Hi everyone,
I'm running into a strange issue with my Xen Orchestra (from Source) backups since this weekend. My daily delta backup job is failing consistently. The main error message points to a timeout when trying to access the NFS remote storage.
Here is a typical error log from the job:

{
  "data": {
    "mode": "delta",
    "reportWhen": "always"
  },
  "id": "1777873224975",
  "jobId": "ba5a00a1-8b9b-4707-b0fd-72a0a46053e5",
  "jobName": "Daily Backup",
  "message": "backup",
  "scheduleId": "016edaaf-25a2-451c-a89b-bcabc03f560e",
  "start": 1777873224975,
  "status": "failure",
  "tasks": [
    {
      "id": "0moqrzs5q-j75xnq751c",
      "start": 1777873525838,
      "status": "failure",
      "end": 1777873525839,
      "result": {
        "remoteId": "e5111a0a-5e8a-4238-8a55-cfdf28495867",
        "message": "timeout while getting the remote e5111a0a-5e8a-4238-8a55-cfdf28495867",
        "name": "Error",
        "stack": "Error: timeout while getting the remote e5111a0a-5e8a-4238-8a55-cfdf28495867\n    at AbstractRunner._getAdapter (file:///opt/xen-orchestra/@xen-orchestra/backups/_runners/_Abstract.mjs:33:88)\n    at file:///opt/xen-orchestra/@xen-orchestra/backups/_runners/VmsXapi.mjs:76:78\n    at Array.map (<anonymous>)\n    at VmsXapiBackupRunner.run (file:///opt/xen-orchestra/@xen-orchestra/backups/_runners/VmsXapi.mjs:76:63)\n    at BackupWorker.run (file:///opt/xen-orchestra/@xen-orchestra/backups/_backupWorker.mjs:68:8)\n    at file:///opt/xen-orchestra/@xen-orchestra/backups/_backupWorker.mjs:188:32\n    at /opt/xen-orchestra/@vates/task/index.js:75:40\n    at AsyncLocalStorage.run (node:internal/async_local_storage/async_context_frame:63:14)\n    at Task.runInside (/opt/xen-orchestra/@vates/task/index.js:204:41)\n    at Task.run (/opt/xen-orchestra/@vates/task/index.js:188:31)"
      },
      "message": "get remote adapter",
      "data": {
        "id": "e5111a0a-5e8a-4238-8a55-cfdf28495867",
        "type": "remote"
      }
    }
  ],
  "end": 1777873525843
}

Now, here is the confusing part:
In Settings -> Remotes, the NFS remote is shown with a green light and appears to be perfectly fine. If I edit the remote and click the "Test" button, the test succeeds without any errors.
Furthermore, I have SSH'd into the Xen Orchestra server and successfully mounted the exact same NFS share manually using the mount command. I can list and access files without any issues. This confirms that there are no general network, firewall, or NFS permission problems between the XO server and the NAS.
So, the connection seems to be working on a system level and even passes the test in the XO UI, but the actual backup job fails with a timeout.
Has anyone experienced this discrepancy before? What could cause the backup job to time out while all other connection tests succeed?
Any pointers would be greatly appreciated!
Thanks in advance.
Martin

[florent]

is it possible that your NFS need some specific options ( like nfs version ? )

[music9050]

@florent Nothing has changed on the NFS (QNAP NAS) side; I had already been backing up to NFS before. It just stopped working over the weekend.
What I did was commit changes to the master branch and update Ubuntu 24.04.