Java EE application servers usually assume that applications use the frameworks and libraries bundled with the server. This is not the case for Jmix - it relies on Spring, Vaadin and the own version of EclipseLink JPA. So we don’t test Jmix on WebSphere/WebLogic/JBoss servers and don’t recommend using them with Jmix applications.
The recommended way of running Jmix apps packaged as WAR files is using Apache Tomcat application server.