Error TIMEOUT Exception in Python using the googlemaps package

I would like to obtain the coordinates from a series of addresses.

After running the code it shows me the following error after in time, it does not return the coordinates sometimes just for the first address. I do not know if it's a problem with the code or the permissions and strictures of the Google APIKey.

Error:

  File "C:\Users\...\AppData\Local\Continuum\anaconda3\lib\site-packages\googlemaps\client.py", line 210, in _request
    raise googlemaps.exceptions.Timeout()

Timeout

Code:

import pandas as pd

xl = pd.ExcelFile('Prueba.xlsx')
df = xl.parse('Sheet1')
df

#%%
import googlemaps
gmaps_key = googlemaps.Client(key = "...")

#%%

df["LAT"] = None
df["LON"] = None

for i in range (0, len(df), 1):
    geocode_result = gmaps_key.geocode(df.iat[i,0])
    try:
        lat = geocode_result[0]["geometry"]["location"]["lat"]
        lon = geocode_result[0]["geometry"]["location"]["lng"]
        df.iat[i, df.columns.get_loc("LAT")] = lat
        df.iat[i, df.columns.get_loc("LON")] = lon
    except:
        lat = None
        lon = None
df