Q:

RabbitMQ (3.2.x) management plugin produces Javascript (TypeError or undefined) error

After making a modification to a cluster, the following two errors began to persist on the Overview tab on every node of the cluster.
On a 3.2.1 Node:

TypeError: Cannot read property 'connections' of undefined

On a 3.2.2 Node:

undefined: There is no template at js/tmpl/login.ejs

Further, the connection, and channels tabs were empty (even though there were definitely connections to the cluster)
The only suggestions online (which did not work) were to Clear the browser cache.
The errors in the Browser console were as follows:

sammy-0.6.0.min.js : 
  runRoute get #/ 
  404 Not Found get #/ 
  runRoute get #/

A:

After some additional searching, this question turned up.  It addresses a different error related to the statistics database on a much older version of RabbitMQ (2.8.7)
RabbitMQ - Statistics database could not be contacted. Message rates and queue lengths will not be shown
The following command (as suggested in the answer by @a-h) run on only one of the cluster nodes resolved the issue. (NOTE: it was not the node with the statistics DB)

rabbitmqctl eval 'application:stop(rabbitmq_management),
  application:start(rabbitmq_management).'

