i have machine which has very strict proxy. I tried to install libraries offline but this seems to be running into all kind of issues.

Which URL needs to be whitelisted for pip install to work for openpyxl and pyPDF2?

C:Windowssystem32>pip install openpyxl
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 403 Forbidden'))': /simple/openpyxl/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 403 Forbidden'))': /simple/openpyxl/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 403 Forbidden'))': /simple/openpyxl/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 403 Forbidden'))': /simple/openpyxl/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 403 Forbidden'))': /simple/openpyxl/
ERROR: Could not find a version that satisfies the requirement openpyxl (from versions: none)
ERROR: No matching distribution found for openpyxl