Some containers from marketplace don't work troublefree

I downloaded Turnkey Nextcloud 16.1 LXC Container.
First apache-server didn’t start, because of some “nested mode”.
And when I solved the problem and got it to start, my browser shows “internal error”.

Please, describe the problem here and provide additional information below (if applicable) …

Versions of the related components and OS (frontend, hypervisors, VMs):
Hypervisor LXC-Node

Steps to reproduce:

Current results:

Expected results:

OpenNebula simply handles the creation of the container with some default sanitized attributes. If some extra configuration is required to tweak the configuration to run a particular workload inside, feel free to tweak the VM Template. If the configuration required is not supported by the driver you can add it using the raw attribute. You can take a look at the container LXC config at /var/lib/lxc/.