[DiffusionAnalyzer] initial and final structures do not match

Hi, I am using DiffusionAnalyzer to analyze MD results at different temperatures [400, 600, 800]. Here is my code:

from IPython.display import Image
%matplotlib inline

import matplotlib.pyplot as plt
import json
import collections
from pymatgen.core import Structure
from pymatgen.analysis.diffusion_analyzer import DiffusionAnalyzer
file1 = ["test-400/vasprun.xml", "test-600/vasprun.xml", "test-800/vasprun.xml"] 
analyzer1 = DiffusionAnalyzer.from_files(file1, specie="Li", smoothed=False)

When I run it, it showed an error. Hope that someone could help me out.

ValueError: initial and final structures do not match.