Problem with muliproccesing module?

Question

Python

You need to parse the data, open the file, read the urls from there, create an array with these urls.
Since there are a lot of urls, using the multiproccesing module, I create streams, or whatever it is called. The problem is this, everything goes fine until the end of the file comes up, when there are about 30-40 urls left, this error flies out.
And no matter how many pools I set 20 or 3. And no matter how many urls I set, 100 or 5000, the error still crashes. What could be the problem?
PS Added try except wherever possible, anyway.
Part of the source code:

def make_all(url):
  get_data(get_html(url), url)


def main():
  	with open('urls.txt') as file:
  		temp_urls = file.readlines()
  		urls = []
  		for i in temp_urls:
  			url = i.strip()
  			urls.append(url)

  		with Pool(20) as pool:
  			pool.map(make_all, urls)