update config with files in attachment and upload the attached deployment start the EAP server using the attached config go to http://127.0.0.1:8080/not-defined-security-domain/user/index.jsp and login using admin:admin check logs and response for any valuable information what happened There should be shown information regarding cause of the internal server error at least in logs. Note: updating the config using /subsystem=elytron/properties-realm=elytron-security:write-attribute(name=users-properties.plain-text, value=true) is the step needed for successful authentication, still there is no info advising that this is what needs to be done.