Dash callback weird error

Dash Python
1 
UPLOAD_DIRECTORY = "Dash_Folder"
#Callback for dropdown menu
@app.callback(dash.dependencies.Output('Categories', 'value'),[dash.dependencies.Input('Categories', 'options')])
def update_output_dropdown(value):
    return 'You have selected "{}"'.format(value)




        

#Callback for submitting everything.
@app.callback(Output('graph', 'figure'), Input('graph-with-button', 'n_clicks'), Input('Categories', 'value'))
def callback(n_clicks, value):
    if (n_clicks != 0):
         return calculation(n_clicks, value)

ctx = dash.callback_context
def calculation(n_clicks,value):
        if os.path.exists(UPLOAD_DIRECTORY):
            for file in uploaded_files():
                dfs = pd.read_excel(file, sheet_name=value)
                if  value == 'Spikes (Oct 23)':
                    # Define if we analyzing Premium or Cut Spikes
                    # Define if the data is reliable 
                    #Code here
app.layout = html.Div(
    children=[
 #Drop Down Menu for the categories. 
    dcc.Dropdown(
        id = 'Categories',
        options=[
            {'label': 'Spikes (Oct 23)', 'value': 'Spikes'},
            {'label': 'Fasteners', 'value': 'Fasteners'},
            {'label': 'Ballast Level', 'value': 'Ballast Level'},
            {'label': 'Spikes Med', 'value': 'Spikes'},
            {'label': 'Fasteners Med', 'value': 'Fasteners'},
            {'label': 'Ballast Level Med', 'value': 'Ballast Level'},
            {'label': 'Spikes Bad', 'value': 'Spikes'},
            {'label': 'Fasteners Bad', 'value': 'Fasteners'},
            {'label': 'Ballast Level Bad', 'value': 'Ballast Level'}
        ],
        placeholder="Select a category",
        value = "Spikes"
    ),
    #html.Div(id='dd-output-container', children = []),

    html.Form([
    #Enter button Event to trigger app callback for dropdown and upload data to submit what to calculate.
    html.Div(id='graph-with-button'),
    html.Button('Submit',id='submit', n_clicks=0),
    ]),
    

    dcc.Graph(
    id = 'graph'
    ), 
    
    ])```
I get an error that says: Cannot read property 'layout' of null
Here is the Traceback. It is just pure gibberish.

(This error originated from the built-in JavaScript code that runs Dash apps. Click to see the full stack trace or open your browser’s console.)
TypeError: Cannot read property ‘layout’ of null

at t.value (http://127.0.0.1:8050/_dash-component-suites/dash_core_components/async-graph.v1_16_0m1617903285.js:1:12380)

at t.value (http://127.0.0.1:8050/_dash-component-suites/dash_core_components/async-graph.v1_16_0m1617903285.js:1:16413)

at callComponentWillReceiveProps (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:13111:16)

at updateClassInstance (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:13313:9)

at updateClassComponent (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:17242:22)

at beginWork (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:18755:18)

at HTMLUnknownElement.callCallback (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:182:16)

at Object.invokeGuardedCallbackDev (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:231:18)

at invokeGuardedCallback (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.js:286:33)

at beginWork$1 (http://127.0.0.1:8050/_dash-component-suites/dash_renderer/react-dom@16.v1_9_1m1624988823.14.0.j

Could it be because of my n_clicks? I am not sure. Does anyone have any clues?