Following your Dockerfile we get this error
keycloak_1 | 17:20:08,968 INFO [org.jboss.as] (Controller Boot Thread) WFLYSRV0025: Keycloak 11.0.2 (WildFly Core 12.0.3.Final) started in 1170ms - Started 56 of 86 services (39 services are lazy, passive or on-demand)
keycloak_1 | 17:20:09,005 ERROR [org.jboss.as.controller.management-operation] (pool-4-thread-1) WFLYCTL0013: Operation ("list-resource-loader-paths") failed - address: ([("core-service" => "module-loading")]) - failure description: "com.smartmovesystems.keycloak.firebasescrypt"
keycloak_1 | adding module com.smartmovesystems.keycloak.firebasescrypt
keycloak_1 | Module com.smartmovesystems.keycloak.firebasescrypt already exists at /opt/jboss/keycloak/modules/com/smartmovesystems/keycloak/firebasescrypt/main
There seem to be two errors. The first is the one stated in the issue title. The other is that the module is already added (I don't understand where and when). After these lines the image stops.
Any idea?