Initially, the Identity Source Directory Password and Directory User ID was working where the Test Connection reported Test Connection(s) successful.
Users are still searchable in the Security Console via
Identity >
Users >
Manage Existing when selecting the identity source in the Search criteria.
System Activity Monitor reports a directory access error where the exception is:
'javax.resource.spi.ResourceAdapterInternalException: Unable to create managed connection
[LDAP: error code 49 - 80090308: LdapErr: DSID-0C0903A9, comment: AcceptSecurityContext error, data 52e, v1db1]'
The Directory User ID used in the Identity Source Connection(s) was found to be a locked account or the password has been changed.