This is my 4th time installing devstack mitaka on Ubuntu 16.04.1 LTS. Everything works fine until I turnoff the system or reboot it and log in again. I cant run any openstackclient commands in the terminal and every page on the web interface shows an error "Unable to retrieve * ". On the 4th installation, now, it is giving me the following error (e.g on openstack flavor list):

Unable to establish connection to http:// xxx.xxx.xxx.xxx:8774/v2.1 / 86f136e04e754f9ca4049ea12ea0a4b8/ flavors /detail: HTTPConnectionPool(host='xxx.xxx.xxx.xxx', port=8774): Max retries exceeded with url: /v2.1/86f136e04e754f9ca4049ea12ea0a4b8/flavors/detail (Caused by NewConnectionError('<requests.packages.urllib3.connection.HTTPConnection object at 0x7fbd2d04f650>: Failed to establish a new connection: [Errno 111] Connection refused',))

Earlier, on the second and third fresh installation it was giving the error

*Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL. Internal Server Error (HTTP 500)*

here is my local.conf

[[local|localrc]]
DEST=/opt/stack

ADMIN_PASSWORD=openstack
MYSQL_PASSWORD=openstack
RABBIT_PASSWORD=openstack
SERVICE_PASSWORD=openstack
SERVICE_TOKEN=openstack


# Database Backend MySQL
enable_service mysql

# RPC Backend RabbitMQ
enable_service rabbit

# Enable Keystone - OpenStack Identity Service
enable_service key

# Horizon - OpenStack Dashboard Service
enable_service horizon

# Enable Glance - OpenStack Image service
enable_service g-api g-reg

# Enable Cinder - Block Storage service for OpenStack
VOLUME_GROUP="cinder-volumes"
enable_service cinder c-api c-vol c-sch c-bak

# Enable Heat (orchestration) Service
enable_service heat h-api h-api-cfn h-api-cw h-eng

# Enable Tempest - The OpenStack Integration Test Suite
enable_service tempest

# Enable NoVNC
enable_service n-novnc


# Enabling Neutron (network) Service
disable_service n-net
enable_service q-svc
enable_service q-agt
enable_service q-dhcp
enable_service q-l3
enable_service q-meta
enable_service q-metering
enable_service neutron

Q_PLUGIN=ml2
#Q_USE_DEBUG_COMMAND=True
if [ "$Q_PLUGIN" = "ml2" ]; then
  #Q_ML2_TENANT_NETWORK_TYPE=gre
  Q_ML2_TENANT_NETWORK_TYPE=vxlan
  :
fi

SCREEN_LOGDIR=/opt/stack/screen-logs
SYSLOG=True
LOGFILE=~/devstack/stack.sh.log


# Define images to be automatically downloaded during the DevStack built proces$
DOWNLOAD_DEFAULT_IMAGES=False
IMAGE_URLS=http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-x86_64-disk.img

What am I doing wrong. I havent touch any other file. Things works fine with fresh installation but encounter different errors every time I log into the system after a reboot or shutdown after a fresh install....Any help would be greatly appreciated