Failed creating home directory in container - singularity-container

Question

I manage to build a container from DockerHub, shell it with Sudo, successfully installed some software, and even run it with Sudo. However, when I try to shell it as an unprivileged user, it gives me an error. Could someone help me in this? Thank you.
The error is as follows:
> singularity shell miniconda4
Increasing verbosity level (2)
Singularity version: 2.4.2-dist
Exec'ing: /usr/lib/x86_64-linux-gnu/singularity/cli/shell.exec
Evaluating args: 'miniconda4'
VERBOSE: Set messagelevel to: 2
VERBOSE: Initialize configuration file: /etc/singularity/singularity.conf
VERBOSE: Initializing Singularity Registry
VERBOSE: Invoking the user namespace
VERBOSE: Not virtualizing USER namespace: running as SUID
VERBOSE: No autofs bug path in configuration, skipping
VERBOSE: Using session directory: /var/lib/singularity/mnt/session
VERBOSE: Mounting overlay with options: lowerdir=/var/lib/singularity/mnt/container,upperdir=/var/lib/singularity/mnt/overlay/upper,workdir=/var/lib/singularity/mnt/overlay/work
VERBOSE: Running all mount components
VERBOSE: Binding '/etc/localtime' to '/var/lib/singularity/mnt/final//etc/localtime'
VERBOSE: Binding '/etc/hosts' to '/var/lib/singularity/mnt/final//etc/hosts'
VERBOSE: Bind-mounting host /proc
VERBOSE: Mounting /sys
VERBOSE: Bind mounting /dev
VERBOSE: Mounting home directory source into session directory: /home/AD/praposo -> /var/lib/singularity/mnt/session/home/AD/praposo
VERBOSE: Failed to create parent directory /var/lib/singularity/mnt/final/home/AD/praposo
ERROR : Failed creating home directory in container /var/lib/singularity/mnt/final/home/AD/praposo: Operation not supported
ABORT : Retval = 255

Answer 1

For those who are having the same problem, the answer is simple: Just type the command '--writable' when calling the 'singularity shell' command.
It allows any user to create directories. And in this case, I think singularity was trying to mount a home directory when it had no permission to do it (but I'm not sure..). Maybe someone would like to answer what really is the problem here..