I have tried on another server using sudo tox egenconfig and got below error, config got failed to generate as well
log is attached 

py27 runtests: PYTHONHASHSEED='2755139893'
py27 runtests: commands[0] | python setup.py testr --slowest --testr-args=engenconfig
running testr
running=OS_STDOUT_CAPTURE=${OS_STDOUT_CAPTURE:-1} \
OS_STDERR_CAPTURE=${OS_STDERR_CAPTURE:-1} \
OS_TEST_TIMEOUT=${OS_TEST_TIMEOUT:-60} \
${PYTHON:-python} -m subunit.run discover $DISCOVER_DIRECTORY --list
PASSED (id=0)
Slowest Tests
pypy create: /home/stack/kingbird/.tox/pypy
ERROR: InterpreterNotFound: pypy
pep8 create: /home/stack/kingbird/.tox/pep8
pep8 installdeps: hacking<0.11,>=0.10.2
pep8 develop-inst: /home/stack/kingbird
pep8 installed: alembic==0.8.7,amqp==1.4.9,anyjson==0.3.3,appdirs==1.4.0,Babel==2.3.4,beautifulsoup4==4.5.0,cachetools==1.1.6,cliff==2.1.0,cmd2==0.6.8,contextlib2==0.5.4,debtcollector==1.6.0,decorator==4.0.10,enum34==1.1.6,eventlet==0.19.0,fasteners==0.14.1,flake8==2.2.4,funcsigs==1.0.2,functools32==3.2.3.post2,futures==3.0.5,futurist==0.16.0,greenlet==0.4.10,hacking==0.10.2,httplib2==0.9.2,iso8601==0.1.11,Jinja2==2.8,jsonpatch==1.14,jsonpointer==1.10,jsonschema==2.5.1,keystoneauth1==2.10.0,keystonemiddleware==4.7.0,-e git+https://github.com/openstack/kingbird.git@43f048deef164479fd6f89970c7589937b3bb33f#egg=kingbird,kombu==3.0.35,logutils==0.3.3,Mako==1.0.4,MarkupSafe==0.23,mccabe==0.2.1,monotonic==1.1,msgpack-python==0.4.8,netaddr==0.7.18,netifaces==0.10.4,openstacksdk==0.9.1,os-client-config==1.18.0,osc-lib==0.4.1,oslo.concurrency==3.12.0,oslo.config==3.13.0,oslo.context==2.7.0,oslo.db==4.8.0,oslo.i18n==3.8.0,oslo.log==3.12.0,oslo.messaging==5.5.0,oslo.middleware==3.15.0,oslo.policy==1.12.0,oslo.rootwrap==5.0.0,oslo.serialization==2.11.0,oslo.service==1.13.0,oslo.utils==3.16.0,oslo.versionedobjects==1.13.0,Paste==2.0.3,PasteDeploy==1.5.2,pbr==1.10.0,pecan==1.1.2,pep8==1.5.7,pika==0.10.0,pika-pool==0.1.3,positional==1.1.1,prettytable==0.7.2,pycadf==2.3.0,pyflakes==0.8.1,pyinotify==0.9.6,pyparsing==2.1.5,python-cinderclient==1.8.0,python-dateutil==2.5.3,python-editor==1.0.1,python-glanceclient==2.2.0,python-keystoneclient==3.3.0,python-neutronclient==5.0.0,python-novaclient==5.0.0,python-openstackclient==2.6.0,pytz==2016.6.1,PyYAML==3.11,repoze.lru==0.6,requests==2.10.0,requestsexceptions==1.1.3,retrying==1.3.3,rfc3986==0.3.1,Routes==2.3.1,simplejson==3.8.2,singledispatch==3.4.0.3,six==1.10.0,SQLAlchemy==1.0.14,sqlalchemy-migrate==0.10.0,sqlparse==0.2.0,stevedore==1.16.0,Tempita==0.5.2,unicodecsv==0.14.1,waitress==0.9.0,warlock==1.2.0,WebOb==1.6.1,WebTest==2.0.23,wrapt==1.10.8
pep8 runtests: PYTHONHASHSEED='2755139893'
pep8 runtests: commands[0] | flake8
______________________________________________________________________________________________ summary ______________________________________________________________________________________________
ERROR:   py34: could not install deps [-r/home/stack/kingbird/requirements.txt, -r/home/stack/kingbird/test-requirements.txt]; v = InvocationError('/home/stack/kingbird/.tox/py34/bin/pip install -U -r/home/stack/kingbird/requirements.txt -r/home/stack/kingbird/test-requirements.txt (see /home/stack/kingbird/.tox/py34/log/py34-1.log)', 1)
  py27: commands succeeded
ERROR:   pypy: InterpreterNotFound: pypy
  pep8: commands succeeded