cointainer backup stops

A few months ago I made a Proxmox backup server I made a few backups and everything worked but now one of the conatainers is not backed up.
Backup of VMs and other containers works.
On PBS the folder for the backup is created but nothing else happens.

Local backup to proxmox from this conatiner does not work either.

Any ideas ? Have you encountered this before ?

Thanks in advance for any help.