Urbackup stops working on LXC-container

We have an urbackup-server running on debian in a LXC-container on Proxmox in current version. the server stops working from now and then, no login on the webinterface is possible but login through ssh is possible. CPU was normal, NOT 100%. NO errors in syslog. any idea what this could be ?

We tested containers and found they crash / restart randomly, we will never use a container again… we always use full virtual machines for anything now. QNAP use them and not seen an issue with their own products (like Broster Station and QVR Pro) however when we have attempted to use them with different products its never been a good experiance.

Thanks for the reply, we will consider this.