Random Network problems with python under Linux

Question

I'm using the requests module for url fetching under linux (minibian) via ethernet on a raspberry pi 1.

To fetch the data i use a loop over a list of urls:

for url in urllist:
   response = requests.get(url,timeout=5) 

I get randomly the error: "[Errno 101] Network is unreachable requests". Befor i tested the urrlib modul with "urllopen" and the same error. The confusing is the script runs under Windows 10 without any error.

So is there a linux network configuration problem?

Thanks in advance!