ValueError: cannot index with vector containing NA / NaN values

The error message means that the dataframe contains blank entries that default to na/NaN.

You can just add na=False in the synatx to fill value for missing values.

import csv
import os
import pandas as pd
os.chdir('C:\\Users\\khalha\\Desktop\\RealExcel')
filename="sales.csv"

Sales = pd.read_csv('sales.csv')
iFlowStatus = Sales[Sales['Product'].str.contains('iFlow', na=False)]['Status']
print(iFlowStatus)