Unexpected HTTP response: 500

Request
{
    "name" => "test",
    "class-name" => "TestClass",
    "address" => [
        ("subsystem" => "elytron"),
        ("custom-credential-security-factory" => "test")
    ],
    "operation" => "add"
}

Response

Internal Server Error
{
    "outcome" => "failed",
    "failure-description" => {
        "WFLYCTL0080: Failed services" => {"org.wildfly.security.security-factory.credential.test" => "org.jboss.msc.service.StartException in service org.wildfly.security.security-factory.credential.test: java.lang.ClassNotFoundException: TestClass from [Module \"org.wildfly.extension.elytron:main\" from local module loader @629f0666 (finder: local module finder @1bc6a36e (roots: /home/pjelinek/servers/7.1.0.DR9/jboss-eap-7.1/modules,/home/pjelinek/servers/7.1.0.DR9/jboss-eap-7.1/modules/system/layers/base))]
    Caused by: java.lang.ClassNotFoundException: TestClass from [Module \"org.wildfly.extension.elytron:main\" from local module loader @629f0666 (finder: local module finder @1bc6a36e (roots: /home/pjelinek/servers/7.1.0.DR9/jboss-eap-7.1/modules,/home/pjelinek/servers/7.1.0.DR9/jboss-eap-7.1/modules/system/layers/base))]"},
        "WFLYCTL0412: Required services that are not installed:" => ["org.wildfly.security.security-factory.credential.test"],
        "WFLYCTL0180: Services with missing/unavailable dependencies" => undefined
    },
    "rolled-back" => true
}