# Keycloak-12.0.4/jdk-16 Standalone on Windows Error when trying to connect to LDAP **URL:** \ **Category:** Getting advice\ **Tags:** user-federation\ **Created:** [April 25, 2021, 12:35am UTC](https://forum.keycloak.org/t/keycloak-12-0-4-jdk-16-standalone-on-windows-error-when-trying-to-connect-to-ldap/8712 "2021-04-25T00:35:54Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![xilonghu](https://avatars.discourse-cdn.com/v4/letter/x/45deac/32.png) [@xilonghu](https://forum.keycloak.org/u/xilonghu)\ **Post date:** [April 25, 2021, 12:35am UTC](https://forum.keycloak.org/t/keycloak-12-0-4-jdk-16-standalone-on-windows-error-when-trying-to-connect-to-ldap/8712/1 "2021-04-25T00:35:54Z")
Hello everyone, Done two testing: 1. Docker jboss/keycloak image, user federation/ldap/active directory works fine. 2. Standalone mode in local machine: After download and setup KeyCloak in my local machine running in standalone mode, got this error for test connection in User Federation/LDAP/Active Directory: Error when trying to connect to LDAP. Here is the detail error in the server log file: 20:19:43,466 ERROR [org.keycloak.services] (default task-4) KC-SERVICES0055: Error when connecting to LDAP: WFLYNAM0027: Failed instantiate InitialContextFactory com.sun.jndi.ldap.LdapCtxFactory from classloader ModuleClassLoader for Module “deployment.keycloak-server.war” from Service Module Loader: javax.naming.NamingException: WFLYNAM0027: Failed instantiate InitialContextFactory com.sun.jndi.ldap.LdapCtxFactory from classloader ModuleClassLoader for Module “deployment.keycloak-server.war” from Service Module Loader [Root exception is java.lang.IllegalAccessException: class org.jboss.as.naming.InitialContext cannot access class com.sun.jndi.ldap.LdapCtxFactory (in module java.naming) because module java.naming does not export com.sun.jndi.ldap to unnamed module @136178c5] at org.jboss.as.naming@21.0.2.Final//org.jboss.as.naming.InitialContext.getDefaultInitCtx(InitialContext.java:120) at org.jboss.as.naming@21.0.2.Final//org.jboss.as.naming.InitialContext.init(InitialContext.java:101) at java.naming/javax.naming.ldap.InitialLdapContext.(InitialLdapContext.java:154) at org.jboss.as.naming@21.0.2.Final//org.jboss.as.naming.InitialContext.(InitialContext.java:91) at org.jboss.as.naming@21.0.2.Final//org.jboss.as.naming.InitialContextFactory.getInitialContext(InitialContextFactory.java:43) at java.naming/javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:719) at java.naming/javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:305) at java.naming/javax.naming.InitialContext.init(InitialContext.java:236) at java.naming/javax.naming.ldap.InitialLdapContext.(InitialLdapContext.java:154) at org.keycloak.keycloak-ldap-federation@12.0.4//org.keycloak.storage.ldap.idm.store.ldap.LDAPContextManager.createLdapContext(LDAPContextManager.java:80) at org.keycloak.keycloak-ldap-federation@12.0.4//org.keycloak.storage.ldap.idm.store.ldap.LDAPContextManager.getLdapContext(LDAPContextManager.java:100) at org.keycloak.keycloak-services@12.0.4//org.keycloak.services.managers.LDAPServerCapabilitiesManager.testLDAP(LDAPServerCapabilitiesManager.java:99) at org.keycloak.keycloak-services@12.0.4//org.keycloak.services.resources.admin.RealmAdminResource.testLDAPConnection(RealmAdminResource.java:953) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:567) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:138) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceMethodInvoker.internalInvokeOnTarget(ResourceMethodInvoker.java:543) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTargetAfterFilter(ResourceMethodInvoker.java:432) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceMethodInvoker.lambda$invokeOnTarget$0(ResourceMethodInvoker.java:393) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:358) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:395) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:364) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:150) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:110) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:141) at org.jboss.resteasy.resteasy-jaxrs@3.13.2.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:104) I’m not a Java developer, so the error message doesn’t help. I did a lot of researching about the error message but didn’t find a solution yet. Could be that I miss configured something? Appreciate your help. ---
**Author:** ![xilonghu](https://avatars.discourse-cdn.com/v4/letter/x/45deac/32.png) [@xilonghu](https://forum.keycloak.org/u/xilonghu)\ **Post date:** [April 25, 2021, 10:50pm UTC](https://forum.keycloak.org/t/keycloak-12-0-4-jdk-16-standalone-on-windows-error-when-trying-to-connect-to-ldap/8712/2 "2021-04-25T22:50:34Z")
I have resolved the issue by installing JDK-11. ---
**Author:** ![Romanovic](https://avatars.discourse-cdn.com/v4/letter/r/0ea827/32.png) [@Romanovic](https://forum.keycloak.org/u/Romanovic)\ **Post date:** [April 26, 2021, 1:23pm UTC](https://forum.keycloak.org/t/keycloak-12-0-4-jdk-16-standalone-on-windows-error-when-trying-to-connect-to-ldap/8712/4 "2021-04-26T13:23:28Z")
Can confirm the same xilonghu. After installing JDK-11 (check that the path of the global variables is correct) it worked for me. Thanks for the suggestion!