Can not fetch index base URL https://pypi.python.org/simple/

[blu-IT]

Hello,

I am trying a booktype install with docker on Ubuntu 18.04.6 LTS.

The first steps went fine, but at step 22 I get the following error:

Step 22/31 : RUN pip install virtualenv     && virtualenv venv     && . venv/bin/activate     && pip install -r Booktype/requirements/prod.txt     && ./Booktype/scripts/createbooktype --database postgresql ${INSTANCENAME}
 ---> Running in af8f4fa59111
Downloading/unpacking virtualenv
  Cannot fetch index base URL https://pypi.python.org/simple/
  Could not find any downloads that satisfy the requirement virtualenv
Cleaning up...
No distributions at all found for virtualenv
Storing debug log for failure in /root/.pip/pip.log
ERROR: Service 'web' failed to build: The command '/bin/sh -c pip install virtualenv     && virtualenv venv     && . venv/bin/activate     && pip install -r Booktype/requirements/prod.txt     && ./Booktype/scripts/createbooktype --database postgresql ${INSTANCENAME}' returned a non-zero code: 1

The mentioned logfile in /root/.pip/pip.log does not exist. I have no idea why the script can not fetch index base URL https://pypi.python.org/simple/ .

Any idea?

Thanks!