Hi, we are getting some issues while modifying the LDAP on Production. We restarted LDAP instance but same issue persist. I request you to suggest on this . Let us know if you need any further information . I can read an entry From Cricetid via the VirtIP [u5356968@cricetid ~]$ldapsearch -x -LLL -h 192.168.154.33 -b "o=mobistar.be" "uid=u5356968" cn dn: uid=u5356968,ou=Techmahindra,ou=Partners,o=mobistar.be cn: DEMOULIN Philippe From Mousedeer to Mousedeer u5356968@mousedeer # ldapsearch -x -LLL -p 3898 -h 192.168.154.97 -b "o=mobistar.be" "uid=u5356968" cn dn: uid=u5356968,ou=Techmahindra,ou=Partners,o=mobistar.be cn: DEMOULIN Philippe But we cannot modify the entry. u5356968@mousedeer # ldapmodify -p 3898 -h 192.168.154.97 -D"cn=directory manager, o=mobistar.be" -w8ZQ7HUJS dn: uid=013tes3477,ou=Dealer Users,ou=Partners,o=mobistar.be changetype: add add: mail mail: 013test.test_osp_fr_hq(a)orange.be adding new entry "uid=013tes3477,ou=Dealer Users,ou=Partners,o=mobistar.be" ldap_add: Undefined attribute type (17) additional info: add: attribute type undefined This is the error I get: Error while executing LDIF - [LDAP: error code 17 - Undefined Attribute Type] java.lang.Exception: [LDAP: error code 17 - Undefined Attribute Type] at org.apache.directory.studio.connection.core.io.api.DirectoryApiConnectionWrapper.checkResponse(DirectoryApiConnectionWrapper.java:1280) at org.apache.directory.studio.connection.core.io.api.DirectoryApiConnectionWrapper.access$600(DirectoryApiConnectionWrapper.java:109) at org.apache.directory.studio.connection.core.io.api.DirectoryApiConnectionWrapper$4.run(DirectoryApiConnectionWrapper.java:726) at org.apache.directory.studio.connection.core.io.api.DirectoryApiConnectionWrapper.runAndMonitor(DirectoryApiConnectionWrapper.java:1175) at org.apache.directory.studio.connection.core.io.api.DirectoryApiConnectionWrapper.checkConnectionAndRunAndMonitor(DirectoryApiConnectionWrapper.java:1109) at org.apache.directory.studio.connection.core.io.api.DirectoryApiConnectionWrapper.modifyEntry(DirectoryApiConnectionWrapper.java:748) at org.apache.directory.studio.ldapbrowser.core.jobs.ImportLdifRunnable.importLdifRecord(ImportLdifRunnable.java:514) at org.apache.directory.studio.ldapbrowser.core.jobs.ImportLdifRunnable.importLdif(ImportLdifRunnable.java:272) at org.apache.directory.studio.ldapbrowser.core.jobs.ExecuteLdifRunnable.executeLdif(ExecuteLdifRunnable.java:157) at org.apache.directory.studio.ldapbrowser.core.jobs.ExecuteLdifRunnable.run(ExecuteLdifRunnable.java:123) at org.apache.directory.studio.ldapbrowser.core.jobs.UpdateEntryRunnable.run(UpdateEntryRunnable.java:59) at org.apache.directory.studio.connection.ui.RunnableContextRunner$1.run(RunnableContextRunner.java:112) at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121) [LDAP: error code 17 - Undefined Attribute Type]