I am trying to create monthly composites of NDVI. But I am getting error.

I have this code:

def create_composites(ndvi, vis, band, view, layer_year, year):

    def monthlyComposite(year, month):
        start = ee.Date.fromYMD(year, month, 1)
        end = start.advance(1, 'month')
        composite = ndvi.filterDate(start, end).median()
        return composite.set('year', year).set('month', month).set('system:time_start', start.millis())

    composites = []
    layer_names = []
    visual = view

    for month in range(1, 13):
        composite = monthlyComposite(year, month)
        layer_name = '{}-{:02d}'.format(year, month)
        if visual == 1:
            Map.addLayer(composite.select(band), vis, layer_name+layer_year)
        composites.append(composite)
        layer_names.append(layer_name)
    return composites, layer_names

Here is the NDVI code:

def NDVI_band(image):
    ndvi = image.normalizedDifference(['B8', 'B4']).rename('NDVI') 
    return image.addBands(ndvi)

NDVI_bands = image.map(NDVI_band)

def ndvi_clip(img):
                return img.clip(canada)
clip = with_NDVI_bands.map(ndvi_clip)

ndvi_composites, ndvi_layers = create_composites(clip, ndviVis, 'NDVI', view, layer_year, year)

I am getting this error:

---------------------------------------------------------------------------
HttpError                                 Traceback (most recent call last)
/usr/local/lib/python3.10/dist-packages/ee/data.py in _execute_cloud_call(call, num_retries)
    401   try:
--> 402     return call.execute(num_retries=num_retries)
    403   except googleapiclient.errors.HttpError as e:

11 frames
HttpError: <HttpError 400 when requesting https://earthengine.googleapis.com/projects/project/maps?fields=name&alt=json returned "Image.select: Band pattern 'NDVI' was applied to an Image with no bands. See https://developers.google.com/earth-engine/guides/debugging#no-bands". Details: "Image.select: Band pattern 'NDVI' was applied to an Image with no bands. See https://developers.google.com/earth-engine/guides/debugging#no-bands">

During handling of the above exception, another exception occurred:

EEException                               Traceback (most recent call last)
/usr/local/lib/python3.10/dist-packages/ee/data.py in _execute_cloud_call(call, num_retries)
    402     return call.execute(num_retries=num_retries)
    403   except googleapiclient.errors.HttpError as e:
--> 404     raise _translate_cloud_exception(e)  # pylint: disable=raise-missing-from
    405 
    406 

EEException: Image.select: Band pattern 'NDVI' was applied to an Image with no bands. See https://developers.google.com/earth-engine/guides/debugging#no-bands

I have tried to debug to find out in which part of the code, the bands are empty/not NDVI and I figured out that in the create_composites function, composite is returning empty bands list. I have successfully run this code a few months ago but now I am facing this error.

Can someone please suggest a solution?