Sphinx firmwared - Only works with remote firmware

On Sphinx call, when I use the remote address of the firmware, everything works fine, however, when I put a local path to the firmware, it does not seem to find the file.

what works:

what does not work:

Is your local path an absolute path? Do you see an error message in sphinx logs?

yes I tried the absolute path and it does not work. Only the URL works.
However it can get files that are not under my current user. Files under opt/… are OK.

It looks like a permission issue. You will probably see the reason for this failure in ulog logs: Troubleshooting - 2.15.1