Bar plot in plotly error: Not all x-axis values

Question

I have a dataframe in which the column Segment Name contains 4 possible values: Lowest, Low, Middle and Higher. When I represent my bar plot in a dashboard, it only shows Lowest and Low in the x-axis.

The code that I use is the following one:

#Load dataframes
df = pd.read_sql('SELECT * FROM Companies_Public', con=db_connection)
print (df[df['SegmentName']=='4 - Higher']) # It returns correctly the values

#Configure data and layout
data = []
for IndustryName in df['IndustryName'].unique():
    trace = go.Bar(
        x=df['SegmentName'],
        y=df[df['IndustryName']==IndustryName]['FinalPointsPerDemography'],
        name = IndustryName)
    data.append(trace)

layout = go.Layout(
    title = 'Bar Plot',
    barmode='stack')

#Configure figure
app.layout = html.Div([
    dcc.Graph(
        id='barplot',
        figure=go.Figure(data=data, layout=layout)
    )
])

if __name__ == '__main__':
    app.run_server()

Does anyone know which could be the reason? Thanks in advance