Error on running securityadmin.sh

I have ran this command plugins/opendistro_security/tools/securityadmin.sh -cacert /usr/share/elasticsearch/config/intermediate-ca.pem -cert /usr/share/elasticsearch/config/certificate.pem and getting the following error:

ERR: An unexpected IllegalStateException occured: failed to load plugin class [com.amazon.opendistroforelasticsearch.security.OpenDistroSecurityPlugin]

Trace:

java.lang.IllegalStateException: failed to load plugin class [com.amazon.opendistroforelasticsearch.security.OpenDistroSecurityPlugin]

at org.elasticsearch.plugins.PluginsService.loadPlugin(PluginsService.java:607)

at org.elasticsearch.plugins.PluginsService.<init>(PluginsService.java:112)

at org.elasticsearch.client.transport.TransportClient.newPluginService(TransportClient.java:108)

at org.elasticsearch.client.transport.TransportClient.buildTemplate(TransportClient.java:133)

at org.elasticsearch.client.transport.TransportClient.<init>(TransportClient.java:273)

at com.amazon.opendistroforelasticsearch.security.tools.OpenDistroSecurityAdmin$TransportClientImpl.<init>(OpenDistroSecurityAdmin.java:893)

at com.amazon.opendistroforelasticsearch.security.tools.OpenDistroSecurityAdmin.main0(OpenDistroSecurityAdmin.java:453)

at com.amazon.opendistroforelasticsearch.security.tools.OpenDistroSecurityAdmin.main(OpenDistroSecurityAdmin.java:133)

Caused by: java.lang.reflect.InvocationTargetException

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)

at org.elasticsearch.plugins.PluginsService.loadPlugin(PluginsService.java:598)

... 7 more

Caused by: ElasticsearchException[Empty file path for opendistro_security.ssl.transport.pemkey_filepath]

at com.amazon.opendistroforelasticsearch.security.ssl.DefaultOpenDistroSecurityKeyStore.checkPath(DefaultOpenDistroSecurityKeyStore.java:813)

at com.amazon.opendistroforelasticsearch.security.ssl.DefaultOpenDistroSecurityKeyStore.resolve(DefaultOpenDistroSecurityKeyStore.java:223)

at com.amazon.opendistroforelasticsearch.security.ssl.DefaultOpenDistroSecurityKeyStore.initSSLConfig(DefaultOpenDistroSecurityKeyStore.java:340)

at com.amazon.opendistroforelasticsearch.security.ssl.DefaultOpenDistroSecurityKeyStore.<init>(DefaultOpenDistroSecurityKeyStore.java:164)

at com.amazon.opendistroforelasticsearch.security.ssl.OpenDistroSecuritySSLPlugin.<init>(OpenDistroSecuritySSLPlugin.java:206)

at com.amazon.opendistroforelasticsearch.security.OpenDistroSecurityPlugin.<init>(OpenDistroSecurityPlugin.java:222)

... 12 more

What am I missing here?

-key option is missing.