Problem starting Django container in production (Whitenoise?)

Question

I have suddenly started having trouble starting up my website in production after I moved to a new VPS hosting service. I was using Vultr and moved to Digitalocean because response time was way faster when using Ansible (for the same machine configuration). In both cases I was using Ubuntu 23.10 as a host. I also tried to do "compose up" with production.yml in my dev machine and the error is the same, so I guess it has nothing to do with the change of hosting service. Here's an extract of Docker's output:

cymentcom-django-1    | PostgreSQL is available
cymentcom-django-1    | Post-processing 'vendor/purecounter/purecounter_vanilla.js' failed!
cymentcom-django-1    |
cymentcom-django-1    | Traceback (most recent call last):
cymentcom-django-1    |   File "/app/manage.py", line 39, in <module>
cymentcom-django-1    |     execute_from_command_line(sys.argv)
cymentcom-django-1    |   File "/usr/local/lib/python3.11/site-packages/django/core/management/__init__.py", line 442, in execute_from_command_line
cymentcom-django-1    |     utility.execute()
cymentcom-django-1    |   File "/usr/local/lib/python3.11/site-packages/django/core/management/__init__.py", line 436, in execute
cymentcom-django-1    |     self.fetch_command(subcommand).run_from_argv(self.argv)
cymentcom-django-1    |   File "/usr/local/lib/python3.11/site-packages/django/core/management/base.py", line 412, in run_from_argv
cymentcom-django-1    |     self.execute(*args, **cmd_options)
cymentcom-django-1    |   File "/usr/local/lib/python3.11/site-packages/django/core/management/base.py", line 458, in execute
cymentcom-django-1    |     output = self.handle(*args, **options)
cymentcom-django-1    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cymentcom-django-1    |   File "/usr/local/lib/python3.11/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 209, in handle
cymentcom-django-1    |     collected = self.collect()
cymentcom-django-1    |                 ^^^^^^^^^^^^^^
cymentcom-django-1    |   File "/usr/local/lib/python3.11/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 154, in collect
cymentcom-django-1    |     raise processed
cymentcom-django-1    | whitenoise.storage.MissingFileError: The file 'vendor/purecounter/purecounter_vanilla.js.map' could not be found with <whitenoise.storage.CompressedManifestStaticFilesStorage object at 0xffffb9388650>.
cymentcom-django-1    |
cymentcom-django-1    | The JS file 'vendor/purecounter/purecounter_vanilla.js' references a file which could not be found:
cymentcom-django-1    |   vendor/purecounter/purecounter_vanilla.js.map
cymentcom-django-1    |
cymentcom-django-1    | Please check the URL references in this JS file, particularly any
cymentcom-django-1    | relative paths which might be pointing to the wrong location.
cymentcom-django-1    |
cymentcom-django-1 exited with code 1

There seems to be a problem with static content served by Whitenoise not being found, but I don't know where or how to investigate any further.

Thanks for your help! (And, needless to say, for having built and maintained this cookiecutter) Alan