This article describes an issue where a Lightweight Directory Access Protocol (LDAP) agent fails during registration and returns an HTTP 400 error. The error occurs when reinstalling the agent or attempting to install a previous version.

[ 2026-01-08 23:38:23.238 ] [ main ] [ INFO ] [LdapAgentConfigLoader:622] - Device Authorization successfully completed.

[ 2026-01-08 23:38:24.067 ] [ main ] [ INFO ] [LdapAgentRuntime:41] - Starting Okta LDAP Agent

[ 2026-01-08 23:38:24.105 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1225] - Loading config file: configFilePath

[ 2026-01-08 23:38:24.147 ] [ main ] [ INFO ] [LdapAgentRuntime:65] - FIPS mode disabled

[ 2026-01-08 23:38:24.257 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1497] - Loading Config from file

[ 2026-01-08 23:38:24.259 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1225] - Loading config file: configFilePath

[ 2026-01-08 23:38:24.262 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1236] - Loading additional config file: additionalConfigFilePath

[ 2026-01-08 23:38:24.266 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1256] - Loading property key from Keystore file

[ 2026-01-08 23:38:24.461 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1305] - Property key loaded from the keystore

[ 2026-01-08 23:38:24.481 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1380] - Agent configured with maxConnectionsPerHost=10

[ 2026-01-08 23:38:24.487 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1505] - Loading Config successful

[ 2026-01-08 23:38:28.420 ] [ main ] [ INFO ] [LdapAgentConfigLoader:636] - Registration started.

[ 2026-01-08 23:38:28.423 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1225] - Loading config file: configFilePath

[ 2026-01-08 23:38:34.419 ] [ main ] [ INFO ] [UnboundIDLdapClient:140] - Making SSL connection

[ 2026-01-08 23:38:35.499 ] [ main ] [ INFO ] [UnboundIDLdapClient:154] - Attempting to connect to <domain.org>:636 ...

[ 2026-01-08 23:38:36.201 ] [ main ] [ INFO ] [UnboundIDLdapClient:160] - Successfully connected to <domain.org>:636!

[ 2026-01-08 23:38:36.297 ] [ main ] [ INFO ] [UnboundIDLdapClient:164] - Connected bind successful

[ 2026-01-08 23:38:41.625 ] [ main ] [ INFO ] [LdapAgentConfigLoader:1441] - Registering new LDAP Domain with Okta

[ 2026-01-08 23:38:41.633 ] [ main ] [ INFO ] [LdapRestClient:358] - Registering domain=<domain.org>

[ 2026-01-08 23:38:41.718 ] [ main ] [ INFO ] [LdapRestClient:652] - POST https://<https://www.google.com/search?q=domain.okta.com>/api/1/internal/app/agent/ldap_sun_one/

[ 2026-01-08 23:38:42.535 ] [ main ] [ ERROR ] [LdapRestClient:389] - Domain registration failed. HTTP error code=400, Reason=Bad Request

[ 2026-01-08 23:38:42.540 ] [ main ] [ ERROR ] [LdapAgentRuntime:94] - Agent encountered runtime error: message=Failed to register LDAP Domain with Okta, cause={}

[ com.okta.agent.AgentRuntimeException: Failed to register LDAP Domain with Okta

[ at com.okta.ldap_agent.config.LdapAgentConfigLoader.registerNewAgent(LdapAgentConfigLoader.java:1445)

[ at com.okta.ldap_agent.config.LdapAgentConfigLoader.performRegister(LdapAgentConfigLoader.java:689)

[ at com.okta.ldap_agent.config.LdapAgentConfigLoader.setupOrStartAgent(LdapAgentConfigLoader.java:279)

[ at com.okta.ldap_agent.LdapAgentRuntime.main(LdapAgentRuntime.java:78)

[ Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input

[ at [Source: (String)""; line: 1, column: 0]

[ at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)

[ at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:4821)

[ at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4723)

[ at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3677)

[ at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3645)

[ at com.okta.ldap_agent.api.http.LdapRestClient.registerDomain(LdapRestClient.java:390)

[ at com.okta.ldap_agent.config.LdapAgentConfigLoader.registerNewAgent(LdapAgentConfigLoader.java:1443)

[ ... 3 common frames omitted

• Lightweight Directory Access Protocol (LDAP) agent
• Directory integrations
• Okta Identity Engine (OIE)
• Okta Classic Engine

An inactive LDAP directory integration exists in the organization for the same LDAP root domain. A backend change prevents agent registration when an inactive integration for the same domain is present.

1. Choose Directory > Directory Integrations > Inactive.
2. Delete the inactive LDAP integration.
3. Rerun the LDAP agent installation and registration.