Anaconda: The system cannot find the file (Molpx library)

Question

I'm trying to use molmpx in Jupyter Notebook on a Anaconda env. I installed it with pip directly on the notebook and restarted the kernel, but then i get this error.

FileNotFoundError                         Traceback (most recent call last)
Cell In[12], line 1
----> 1 import molpx
      2 import warnings
      3 get_ipython().run_line_magic('matplotlib', 'ipympl')

File ~\anaconda3\envs\santiago\Lib\site-packages\molpx\__init__.py:162
    159     return True
    161 # Try to help the user getting molpx working out of the box and raise an Exception if molpx wont work
--> 162 if not all(_get_extension_status().values()):
    163     for _ext, _enabled in _get_extension_status().items():
    164         if not _enabled:

File ~\anaconda3\envs\santiago\Lib\site-packages\molpx\__init__.py:119, in _get_extension_status(ext_list)
    111 r"""
    112 Guess the status of the extensions in ext_list. the correct way of doing this
    113 would be using notebook.nbextensions, but you need paths to the extensions
    114 and I dont want to go there
    115 :return: dictionary with extensions in ext_list as keys and True or False as values
    116 """
    117 enabled_exts = {key:None for key in ext_list}
--> 119 lines = _subprocess.check_output(("jupyter-nbextension", "list"), stderr=_subprocess.DEVNULL)
    120 for ext in enabled_exts.keys():
    121     for iline in lines.decode().splitlines():

File ~\anaconda3\envs\santiago\Lib\subprocess.py:466, in check_output(timeout, *popenargs, **kwargs)
    463         empty = b''
    464     kwargs['input'] = empty
--> 466 return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
    467            **kwargs).stdout

File ~\anaconda3\envs\santiago\Lib\subprocess.py:548, in run(input, capture_output, timeout, check, *popenargs, **kwargs)
    545     kwargs['stdout'] = PIPE
    546     kwargs['stderr'] = PIPE
--> 548 with Popen(*popenargs, **kwargs) as process:
    549     try:
    550         stdout, stderr = process.communicate(input, timeout=timeout)

File ~\anaconda3\envs\santiago\Lib\subprocess.py:1026, in Popen.__init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags, restore_signals, start_new_session, pass_fds, user, group, extra_groups, encoding, errors, text, umask, pipesize, process_group)
   1022         if self.text_mode:
   1023             self.stderr = io.TextIOWrapper(self.stderr,
   1024                     encoding=encoding, errors=errors)
-> 1026     self._execute_child(args, executable, preexec_fn, close_fds,
   1027                         pass_fds, cwd, env,
   1028                         startupinfo, creationflags, shell,
   1029                         p2cread, p2cwrite,
   1030                         c2pread, c2pwrite,
   1031                         errread, errwrite,
   1032                         restore_signals,
   1033                         gid, gids, uid, umask,
   1034                         start_new_session, process_group)
   1035 except:
   1036     # Cleanup if the child failed starting.
   1037     for f in filter(None, (self.stdin, self.stdout, self.stderr)):

File ~\anaconda3\envs\santiago\Lib\subprocess.py:1538, in Popen._execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, unused_restore_signals, unused_gid, unused_gids, unused_uid, unused_umask, unused_start_new_session, unused_process_group)
   1536 # Start the process
   1537 try:
-> 1538     hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
   1539                              # no special security
   1540                              None, None,
   1541                              int(not close_fds),
   1542                              creationflags,
   1543                              env,
   1544                              cwd,
   1545                              startupinfo)
   1546 finally:
   1547     # Child is launched. Close the parent's copy of those pipe
   1548     # handles that only the child should have open.  You need
   (...)
   1551     # pipe will not close when the child process exits and the
   1552     # ReadFile will hang.
   1553     self._close_pipe_fds(p2cread, p2cwrite,
   1554                          c2pread, c2pwrite,
   1555                          errread, errwrite)

FileNotFoundError: [WinError 2] The system cannot find the file specified

I installed through conda ipympl because I read that could be in some way related but it's definetly not. Can someone help me with this problem? I really don't know how to handle it.