issues setting fortran in vstudio on Ubuntu 24.04.01

[CeliaLaurent]

Hi,
I've been trying to setup Modern Fortran extension with fortls on vstudio.
I'm running on Ubuntu 24.04.1 LTS, with visual studio code (version 1.92.2).
I installed in visual studio code the 3.4.2024090901 (pre-release) version of the Modern Fortran extension.
I installed fortls pre-release version using pip (python3 -m pip install fortls --pre) within a python 3.11.6 environment
command which forts returns

/PATH/TO/pyenv/versions/3.11.6/envs/pyenv-3.11.6/bin/fortls

and fortls --version returns

3.1.2

fortls folder is at path:

/PATH/TO/pyenv/versions/3.11.6/envs/pyenv-3.11.6/lib/python3.11/site-packages/forts/

and contains:

constants.py fortls.schema.json helper_functions.py interface.py json_templates.py main.py pycache schema.py version.py
debug.py ftypes.py init.py jsonrpc.py langserver.py parsers regex_patterns.py _version.py

I use a settings.json file set as:

{
"extensions.experimental.affinity": {
"asvetliakov.vscode-neovim": 1
},
"fortran.fortls.path": "/PATH/TO/pyenv/versions/3.11.6/envs/pyenv-3.11.6/bin/fortls",
"fortran.logging.level": "Debug"
}

Visual studio code does not show any particular notification of error.
I can open fortran file but and I can get suggestions of completion (the names of the routines/variables do appear) as well as some warning detection, but I don't have per example access to the information regarding the arguments of a subroutine.

Can anyone help me understand what I'm doing wrong?
Thank you