I have configured a Spring Boot project with connection to Keycloak, and also I want to install a Custom SPI User Provider external to Keycloak. I did all the steps to do the Provider and ProviderFactory, and also the file in META-INF/services, and now Wildfly fails with, 14:20:43,656 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-2) MSC000001: Failed to start service jboss.deployment.unit."focusoc-0.0.1-SNAPSHOT.jar".POST_MODULE: org.jboss.msc.service.StartException in service jboss.deployment.unit."focusoc-0.0.1-SNAPSHOT.jar".POST_MODULE: WFLYSRV0153: Failed to process phase POST_MODULE of deployment "focusoc-0.0.1-SNAPSHOT.jar" at org.jboss.as.server@9.0.2.Final//org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:183) at org.jboss.msc@1.4.8.Final//org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1737) at org.jboss.msc@1.4.8.Final//org.jboss.msc.service.ServiceControllerImpl$StartTask.execute(ServiceControllerImpl.java:1699) at org.jboss.msc@1.4.8.Final//org.jboss.msc.service.ServiceControllerImpl$ControllerTask.run(ServiceControllerImpl.java:1557) at org.jboss.threads@2.3.3.Final//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982) at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486) at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: java.util.ServiceConfigurationError: org.keycloak.storage.UserStorageProviderFactory: Provider gcs.fds.focusoc.keycloak.spi.LoginStorageProviderFactory not found at java.base/java.util.ServiceLoader.fail(ServiceLoader.java:588) at java.base/java.util.ServiceLoader$LazyClassPathLookupIterator.nextProviderClass(ServiceLoader.java:1211) at java.base/java.util.ServiceLoader$LazyClassPathLookupIterator.hasNextService(ServiceLoader.java:1220) at java.base/java.util.ServiceLoader$LazyClassPathLookupIterator.hasNext(ServiceLoader.java:1264) at java.base/java.util.ServiceLoader$2.hasNext(ServiceLoader.java:1299) at java.base/java.util.ServiceLoader$3.hasNext(ServiceLoader.java:1384) at org.keycloak.keycloak-services@7.0.0//org.keycloak.provider.DefaultProviderLoader.load(DefaultProviderLoader.java:60) at org.keycloak.keycloak-services@7.0.0//org.keycloak.provider.ProviderManager.load(ProviderManager.java:92) at org.keycloak.keycloak-services@7.0.0//org.keycloak.services.DefaultKeycloakSessionFactory.loadFactories(DefaultKeycloakSessionFactory.java:214) at org.keycloak.keycloak-services@7.0.0//org.keycloak.services.DefaultKeycloakSessionFactory.deploy(DefaultKeycloakSessionFactory.java:115) at org.keycloak.keycloak-services@7.0.0//org.keycloak.provider.ProviderManagerRegistry.deploy(ProviderManagerRegistry.java:42) at org.keycloak.keycloak-wildfly-server-subsystem@7.0.0//org.keycloak.subsystem.server.extension.KeycloakProviderDeploymentProcessor.deploy(KeycloakProviderDeploymentProcessor.java:55) at org.jboss.as.server@9.0.2.Final//org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:176) ... 8 more 14:20:43,657 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 4) WFLYCTL0013: Operation ("add") failed - address: ([("deployment" => "focusoc-0.0.1-SNAPSHOT.jar")]) - failure description: {"WFLYCTL0080: Failed services" => {"jboss.deployment.unit.\"focusoc-0.0.1-SNAPSHOT.jar\".POST_MODULE" => "WFLYSRV0153: Failed to process phase POST_MODULE of deployment \"focusoc-0.0.1-SNAPSHOT.jar\" Caused by: java.util.ServiceConfigurationError: org.keycloak.storage.UserStorageProviderFactory: Provider gcs.fds.focusoc.keycloak.spi.LoginStorageProviderFactory not found"}} 14:20:43,658 ERROR [org.jboss.as.server] (management-handler-thread - 4) WFLYSRV0021: Deploy of deployment "focusoc-0.0.1-SNAPSHOT.jar" was rolled back with the following failure message: {"WFLYCTL0080: Failed services" => {"jboss.deployment.unit.\"focusoc-0.0.1-SNAPSHOT.jar\".POST_MODULE" => "WFLYSRV0153: Failed to process phase POST_MODULE of deployment \"focusoc-0.0.1-SNAPSHOT.jar\" Caused by: java.util.ServiceConfigurationError: org.keycloak.storage.UserStorageProviderFactory: Provider gcs.fds.focusoc.keycloak.spi.LoginStorageProviderFactory not found"}} Anyone knows what it is happening? P Please consider the environment before printing this e-mail.