As explained in the NetIQ iManager Installation Guide, the iManager instructions for dealing with self-signed certificates don’t apply to OES Linux.
OES installs Tomcat and Apache versions that are specific to OES. For instructions on replacing the self-signed Apache/Tomcat certificate on OES, see Section 20.0, Certificate Management.
NOTE:Beginning with OES 23.4, iManager is deprecated and will not be available from OES 25.4. Unified Management Console (UMC) provides customized access to network administration utilities and content from virtually anywhere using the Internet and a web browser similar to iManager. For more information about UMC, see Unified Management Console.