Installed ambari-server and configured password encryption, but chose not to persist master key:

===================
Choose one of the following options:
  [1] Enable HTTPS for Ambari server.
  [2] Encrypt passwords stored in ambari.properties file.
  [3] Setup Ambari kerberos JAAS configuration.
  [4] Setup truststore.
  [5] Import certificate to truststore.
===========================================================================
Enter choice, (1-5): 2
Password encryption is enabled.
Do you want to reset Master Key? [y/n] (n): y
Master Key not persisted.
Enter current Master Key:
Enter new Master Key:
Re-enter master key:
Do you want to persist master key. If you choose not to persist, you need to
provide the Master Key while starting the ambari server as an env variable
named AMBARI_SECURITY_MASTER_KEY or the start will prompt for the master key.
Persist [y/n] (y)? n
Adjusting ambari-server permissions and ownership...
Ambari Server 'setup-security' completed successfully.

Then, export environment variable.

export AMBARI_SECURITY_MASTER_KEY=hadoop

Then, run LDAP setup with the following settings:

ambari-server setup-ldap -v
====================
Review Settings
====================
Primary LDAP Host (ldap.ambari.apache.org):
 ctr-e138-1518143905142-473336-01-000002.hwx.site
Primary LDAP Port (389):  389
Use SSL [true/false] (false):  false
User object class (posixUser):  posixUser
User ID attribute (uid):  uid
Group object class (posixGroup):  posixGroup
Group name attribute (cn):  cn
Group member attribute (memberUid):  memberUid
Distinguished name attribute (dn):  dn
Search Base (dc=ambari,dc=apache,dc=org):  dc=apache,dc=org
Referral method [follow/ignore] (follow):  follow
Bind anonymously [true/false] (false):  false
Handling behavior for username collisions [convert/skip] for LDAP sync (skip):
 skip ambari.ldap.connectivity.bind_dn: uid=hdfs,ou=people,ou=dev,dc=apache,dc=org
ambari.ldap.connectivity.bind_password: *****
Save settings [y/n] (y)? y

Issues:

The issues are seen when master key is not persisted as part of the initial password encryption step.

Go to the folder /usr/lib/ambari-server/web/javascipts using cd /usr/lib/ambari-server/web/javascripts

Take a backup of app.js using cp app.js app.js_backup

Edit the app.js file. Find the line(39892)onNetworkIssuesExist: function () {

Change the line from :

/**
   * Use Local Repo if some network issues exist
   */
  onNetworkIssuesExist: function () {
    if (this.get('networkIssuesExist')) {
      this.get('content.stacks').forEach(function (stack) {
          stack.setProperties({
            usePublicRepo: false,
            useLocalRepo: true
          });
          stack.cleanReposBaseUrls();
      });
    }
  }.observes('networkIssuesExist'),

to

/**
   * Use Local Repo if some network issues exist
   */
  onNetworkIssuesExist: function () {
    if (this.get('networkIssuesExist')) {
      this.get('content.stacks').forEach(function (stack) {
        if(stack.get('useLocalRepo') != true){
          stack.setProperties({
            usePublicRepo: false,
            useLocalRepo: true
          });
          stack.cleanReposBaseUrls();
        }
      });
    }
  }.observes('networkIssuesExist'), 

Reload the page, and then start the create cluster wizard again.