REP-51019: System user authentication is missing : ORACLE

 Make change file rwservlet.properties from

C:\Oracle\Middleware\Oracle_Home\user_projects\domains\base_domain\config\fmwconfig\servers\WLS_REPORTS\applications\reports_12.2.1\configuration\rwservlet.properties

   <singlesignon>no</singlesignon>

   TO

 <singlesignon>yes</singlesignon>


Add below line
<webcommandaccess>L2</webcommandaccess>


In rwserver.conf file, from

C:\Oracle\Middleware\Oracle_Home\user_projects\domains\base_domain\config\fmwconfig\servers\WLS_REPORTS\applications\reports_12.2.1\configuration\rwserver.conf

Change 

<job jobType="report" engineId="rwEng" securityId="rwJaznSec"/>

to

<job jobType="report" engineId="rwEng"/>

And

Comment the line below from

<security id="rwJaznSec" class="oracle.reports.server.RWJAZNSecurity"/> to <!--security id="rwJaznSec" class="oracle.reports.server.RWJAZNSecurity"/-->

Now, stop report server as Administrator and Start it again as Administrator