If you ever see something like this

root@chefserver01:/etc/chef# knife configure -i -V
Overwrite /root/.chef/knife.rb? (Y/N) y
Please enter the chef server URL: [http://chefserver01:4000]
Please enter a clientname for the new client: [root] jtran7
Please enter the existing admin clientname: [chef-webui]
Please enter the location of the existing admin client's private key: [/etc/chef/webui.pem]
Please enter the validation clientname: [chef-validator]
Please enter the location of the validation key: [/etc/chef/validation.pem]
Please enter the path to a chef repository (or leave blank):
Creating initial API user...
INFO: HTTP Request Returned 500 Internal Server Error: Connection reset by peer
ERROR: Server returned error for http://chefserver01:4000/clients, retrying 1/5 in 4s
INFO: HTTP Request Returned 409 Conflict: Client already exists
INFO: HTTP Request Returned 500 Internal Server Error: Connection reset by peer
ERROR: Server returned error for http://chefserver01:4000/clients/jtran7, retrying 1/5 in 4s
INFO: HTTP Request Returned 500 Internal Server Error: Connection reset by peer
ERROR: Server returned error for http://chefserver01:4000/clients/jtran7, retrying 2/5 in 5s

it’s likely your ampq password is incorrect in /etc/chef/server.rb

# amqp_pass sets the password for the AMQP virtual host in rabbitmq-server.
amqp_pass "testing"

If you had deleted your rabbitmq mnesia table you had to do something like this.
The word “testing” is your ampq password

sudo rabbitmqctl add_vhost /chef
sudo rabbitmqctl add_user chef testing
sudo rabbitmqctl set_permissions -p /chef chef ".*" ".*" ".*"