Error creating empty file subvolume - Unable to backup

Howdy folks. I have a freshly deployed Infscape Urbackup appliance as a VM on Proxmox 7. Updated to the latest with a cache drive, connected to Backblaze B2.

I tried to run a simple file backup and I was immediately met with this error in the client logs of my workstation:

Error creating empty file subvolume. "ERROR: cannot access /media/backup/backups/MGMT-01/231202-1725: Input/output error

Cannot create directory /media/backup/backups/MGMT-01/231202-1725 for backup (server error). ERROR: cannot access /media/backup/backups/MGMT-01/231202-1725: Input/output error
Time taken for backing up client MGMT-01: 8ms
Backup failed

Any ideas on how to solve this? No issues with my storage, was able to setup the server OK. Everything is fresh, new sever, new bucket, fresh virtual drive, etc…

Edit: here are some more logs from /var/log/app.log:

2023-12-02 07:06:40,413 INFO: NEW:
auto eth0
iface eth0 inet dhcp
 [in /root/urbackup-app-server/urbackup_app_server/wifi_config.py:674]
2023-12-02 07:09:19,609 INFO: Rebooting system... [in /root/urbackup-app-server/urbackup_app_server/update_firmware.py:102]
2023-12-02 17:11:05,364 INFO: bridged=False wired_type=auto iface=eth0 inet=inet [in /root/urbackup-app-server/urbackup_app_server/wifi_config.py:532]
2023-12-02 17:11:05,368 INFO: bridged=False wired_type=disabled iface=eth0 inet=inet6 [in /root/urbackup-app-server/urbackup_app_server/wifi_config.py:532]
2023-12-02 17:11:05,442 ERROR: (<class 'sh.ErrorReturnCode_5'>, ErrorReturnCode_5('\n\n  RAN: /bin/systemctl restart session-1.scope\n\n  STDOUT:\n\n\n  STDERR:\nFailed to restart session-1.scope: Unit session-1.scope not found.\n'), <t>  File "/root/urbackup-app-server/startup.py", line 64, in refresh_issue
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 1524, in __call__
    return RunningCommand(cmd, call_args, stdin, stdout, stderr)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 788, in __init__
    self.wait()
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 845, in wait
    self.handle_command_exit_code(exit_code)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 869, in handle_command_exit_code
    raise exc
sh.ErrorReturnCode_5:

  RAN: /bin/systemctl restart session-1.scope

  STDOUT:


  STDERR:
Failed to restart session-1.scope: Unit session-1.scope not found.

 [in /root/urbackup-app-server/urbackup_app_server/__init__.py:179]
2023-12-02 17:11:07,140 WARNING: Session invalid. Logging in... [in /root/urbackup-app-server/urbackup_app_server/download_json.py:234]
2023-12-02 17:16:08,119 INFO: Creating partition table... [in /root/urbackup-app-server/urbackup_app_server/partition.py:3090]
2023-12-02 17:16:08,246 INFO: Done. [in /root/urbackup-app-server/urbackup_app_server/partition.py:3103]
2023-12-02 17:16:08,254 ERROR: (<class 'FileNotFoundError'>, FileNotFoundError(2, 'No such file or directory'), <traceback object at 0x7f9c0ac4f8c0>) Traceback (most recent call last):
  File "/root/urbackup-app-server/urbackup_app_server/partition.py", line 565, in read_devices
FileNotFoundError: [Errno 2] No such file or directory: '/dev/disk/by-partlabel'
 [in /root/urbackup-app-server/urbackup_app_server/__init__.py:179]
2023-12-02 17:16:08,278 INFO: Waiting for partition /dev/disk/by-partlabel/CC-b2d9b8095dba431f87e05065a614d4e8... [in /root/urbackup-app-server/urbackup_app_server/partition.py:2452]
2023-12-02 17:16:08,779 INFO: Creating crypto header... [in /root/urbackup-app-server/urbackup_app_server/partition.py:2481]
2023-12-02 17:16:16,987 INFO: Done. [in /root/urbackup-app-server/urbackup_app_server/partition.py:2498]
2023-12-02 17:16:16,987 INFO: Opening crypto device... [in /root/urbackup-app-server/urbackup_app_server/partition.py:2516]
2023-12-02 17:16:22,880 INFO: Opened crypto device. Mapper name: LUKS-CC-b2d9b8095dba431f87e05065a614d4e8 [in /root/urbackup-app-server/urbackup_app_server/partition.py:2536]
2023-12-02 17:16:22,880 INFO: Waiting for mapper... [in /root/urbackup-app-server/urbackup_app_server/partition.py:2545]
2023-12-02 17:16:22,889 INFO: Mapper found. [in /root/urbackup-app-server/urbackup_app_server/partition.py:2551]
2023-12-02 17:16:22,889 INFO: Creating btrfs filesystem... [in /root/urbackup-app-server/urbackup_app_server/partition.py:2654]
2023-12-02 17:16:23,530 INFO: Done. [in /root/urbackup-app-server/urbackup_app_server/partition.py:2660]
2023-12-02 17:16:23,576 INFO: Stopping tclouddrive add_new_device [in /root/urbackup-app-server/urbackup_app_server/partition.py:2676]
2023-12-02 17:16:33,607 INFO: Mounting storage... [in /root/urbackup-app-server/urbackup_app_server/partition.py:2723]
2023-12-02 17:16:38,026 INFO: Setup s3 stop tclouddrive [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:183]
2023-12-02 17:16:38,034 INFO: Saving new clouddrive settings... [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:189]
2023-12-02 17:16:38,116 INFO: Mount status file gone/empty [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:91]
2023-12-02 17:16:39,126 INFO: Import state dl_magic_file [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:69]
2023-12-02 17:16:58,325 INFO: Import state delete_objects [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:69]
2023-12-02 17:17:03,377 INFO: Import state ready [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:69]
2023-12-02 17:17:04,387 INFO: Import state mounting [in /root/urbackup-app-server/urbackup_app_server/clouddrive.py:69]
2023-12-02 17:18:49,926 INFO: Backing up etc... [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:174]
2023-12-02 17:18:49,943 INFO: Backing up database... [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:185]
2023-12-02 17:18:49,944 INFO: Mounting root file system... [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:51]
2023-12-02 17:18:49,952 INFO: Creating read only snapshot... [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:223]
2023-12-02 17:18:50,006 INFO: Syncing... [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:228]
2023-12-02 17:18:50,026 INFO: Sending full... [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:236]
2023-12-02 17:18:50,041 ERROR: Error running database backup (rc=1): (errs: At subvol /media/fs/urbackup_ro
At subvol urbackup_ro
ERROR: creating subvolume urbackup_ro failed: Input/output error
) (out: ) send_cmd: btrfs send /media/fs/urbackup_ro [in /root/urbackup-app-server/urbackup_app_server/backup_db.py:81]
2023-12-02 17:18:50,055 ERROR: New event id internal_db_backup_fail subj: GP-BSA-609E: Internal database backup is failing [in /root/urbackup-app-server/events.py:47]
2023-12-02 17:18:50,056 ERROR: New event msg: Internal database backup to backup storage is currently failing. Please contact support (report problem link on the bottom).

Alternatively, the log file at /var/log/app.log might contain more information about the error cause. [in /root/urbackup-app-server/events.py:48]
2023-12-02 17:18:57,778 ERROR: Exception on /cleanup_system [GET] [in /root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py:1744]
Traceback (most recent call last):
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 2528, in wsgi_app
    response = self.full_dispatch_request()
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 1826, in full_dispatch_request
    return self.finalize_request(rv)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 1845, in finalize_request
    response = self.make_response(rv)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 2137, in make_response
    raise TypeError(
TypeError: The view function for 'cleanup_system' did not return a valid response. The function either returned None or ended without a return statement.
2023-12-02 17:18:57,789 ERROR: Exception on /run_trim [GET] [in /root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py:1744]
Traceback (most recent call last):
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 2528, in wsgi_app
    response = self.full_dispatch_request()
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 1825, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 1823, in full_dispatch_request
    rv = self.dispatch_request()
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/root/urbackup-app-server/urbackup_app_server/clouddrive.py", line 980, in run_trim
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 1524, in __call__
    return RunningCommand(cmd, call_args, stdin, stdout, stderr)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 788, in __init__
    self.wait()
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 845, in wait
    self.handle_command_exit_code(exit_code)
  File "/root/.virtualenvs/main/lib/python3.9/site-packages/sh.py", line 869, in handle_command_exit_code
    raise exc
sh.ErrorReturnCode_1:

  RAN: /sbin/fstrim /media/cloudcache

  STDOUT:


  STDERR:
fstrim: /media/cloudcache: the discard operation is not supported

2023-12-02 17:21:22,743 ERROR: _get_response exception: (<class 'OSError'>, OSError(101, 'Network is unreachable'), <traceback object at 0x7f915b4a6480>) [in /root/urbackup-app-server/urbackup_app_server/download_json.py:188]
2023-12-02 17:21:23,729 INFO: Uploading encryption key b2d9b8095dba431f87e05065a614d4e8... [in /root/urbackup-app-server/urbackup_app_server/partition.py:4790]
2023-12-02 17:21:24,720 INFO: Encryption key uploaded successfully [in /root/urbackup-app-server/urbackup_app_server/partition.py:4808]
2023-12-02 17:21:24,730 INFO: Uploading encryption key b'68769adea05f799fa055a85b5bb060fbda34411f'... [in /root/urbackup-app-server/urbackup_app_server/partition.py:4790]
2023-12-02 17:21:25,760 INFO: Encryption key uploaded successfully [in /root/urbackup-app-server/urbackup_app_server/partition.py:4808]