Recently working with Flask and using Apache2 as WSGI a new error appeared in the apache logs for a new feature added to the API in Flask:

The problem appears because I’ve installed the wrong WSGI module  for apache:

I hadn’t installed the ldap module for Python 3.5 (but I did for python 2.7) (this is one of the reasons to use virtual environments more often, my fault).

Anyway, all my development is currently in Python 2.7, so I won’t need that module but the 2.7 version:

I’ve printed the sys environment of python following the advice in this serverfault post and it confirmed what I already knew.