Step 1: Building Docker image fails at pip install beautifulsoup4

[mmoga-uf]

When running docker image build -t linkextractor:step1 . in the tutorial, the build fails at:

 => [2/6] RUN        pip install beautifulsoup4                         192.3s
 => => # e in name resolution')': /simple/beautifulsoup4/
 => => # WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=N
 => => # one, status=None)) after connection broken by 'NewConnectionError('<p
 => => # ip._vendor.urllib3.connection.HTTPSConnection object at 0x7f6cc19f4f5
 => => # 0>: Failed to establish a new connection: [Errno -3] Temporary failur
 => => # e in name resolution')': /simple/beautifulsoup4/

This is the error message:

=> ERROR [2/6] RUN        pip install beautifulsoup4                   236.0s
------
 > [2/6] RUN        pip install beautifulsoup4:
35.88 WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None,
 status=None)) after connection broken by 'NewConnectionError('<pip._vendor.url
lib3.connection.HTTPSConnection object at 0x7f6cc19ed6a0>: Failed to establish
a new connection: [Errno -3] Temporary failure in name resolution')': /simple/b
eautifulsoup4/
68.41 WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f6cc19f47d0>: Failed to establisha new connection: [Errno -3] Temporary failure in name resolution')': /simple/beautifulsoup4/
101.4 WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f6cc19f4a50>: Failed to establisha new connection: [Errno -3] Temporary failure in name resolution')': /simple/beautifulsoup4/
135.5 WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f6cc19f4cd0>: Failed to establisha new connection: [Errno -3] Temporary failure in name resolution')': /simple/beautifulsoup4/
171.5 WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f6cc19f4f50>: Failed to establisha new connection: [Errno -3] Temporary failure in name resolution')': /simple/beautifulsoup4/
203.5 ERROR: Could not find a version that satisfies the requirement beautifulsoup4 (from versions: none)
235.7 ERROR: No matching distribution found for beautifulsoup4
------
Dockerfile:4
--------------------
   2 |     LABEL      maintainer="Sawood Alam <@ibnesayeed>"
   3 |
   4 | >>> RUN        pip install beautifulsoup4
   5 |     RUN        pip install requests
   6 |
--------------------
ERROR: failed to solve: process "/bin/sh -c pip install beautifulsoup4" did not complete successfully: exit code: 1