Scheduled backups "no valid previous backup" / Manual Backup works fine

[eisteed]

Hello everybody, I'm pretty new to Proxmox Backup Server and here's my setup :

I'm hosting PVE on a physical server, hosting 4 VMs and 1 container.

The container is debian with proxmox backup server installed on it, unprivileged is unchecked as I wanted simple direct access to my physical drive.
I mounted my harddrive /dev/sdd1 with PVE to /mnt/pve/backup4t and mounted it to my container like so :
mp0: /dev/sdd1,mp=/mnt/pve/backup4t,backup=0

Then created a datastore inside PBS using that mount point.

When I run a backup for the first time everything goes normally
When I manually run a backup from PVE (going to the VM and clicking Backup Now), PBS find the last backup and does incremental backup

But if I schedule a backup inside PVE using PBS as storage, when the backup run, PBS get this error :
GET /previous: 400 Bad Request: no valid previous backup

And creates a full new backup.
All folders of my datastore are owned by backup:backup so I don't think it's a permissions issue.

Any help much appreciated, Thank you.

EDIT: I also just tried to run backup from the backup schedule inside PVE
Datacenter -> backup -> select my backup task -> run now

Last backup is correctly detected, hard to find what's causing an issue when the backup run as scheduled..

 

[eisteed]

My daily scheduled backups seems to be running fine now.
no more GET /previous: 400 Bad Request: no valid previous backup
Mystery solved by another..