Problem changing username on LDAP

Description:

Hello,

I have been using rocket.chat with ldap connection since 3 years. Every thing is working great.
The user name is about to change fot all users in our LDAP directory.
But if I change the username of one user in LDAP, and try to connect to RocketChat, the user is not found and I am getting this error in the logs :

{"level":50,"time":"2025-05-05T14:33:22.175Z","pid":93659,"hostname":"CDLC-CHAT","name":"Data Importer - LDAPUserConverter","err":{"type":"errorClass","message":"Email already exists. [403]","stack":"Error: Email already exists. [403]
at AccountsServer.insertUserDoc (packages/accounts-base/accounts_server.js:1223:15)
at processTicksAndRejections (node:internal/process/task_queues:105:5)
at AccountsServer.Accounts.insertUserDoc (app/authentication/server/startup/index.js:323:14)
at LDAPUserConverter.insertOrUpdateUser (app/importer/server/classes/converters/UserConverter.ts:241:19)
at LDAPUserConverter.convertRecord (app/importer/server/classes/converters/UserConverter.ts:53:3)
at LDAPUserConverter.iterateRecords (app/importer/server/classes/converters/RecordConverter.ts:219:19)
at LDAPUserConverter.convertData (app/importer/server/classes/converters/UserConverter.ts:64:4)
at Function.convertSingleUser (server/lib/ldap/UserConverter.ts:51:3)
at Function.syncUserForLogin (server/lib/ldap/Manager.ts:365:3)
at Function.addLdapUser (server/lib/ldap/Manager.ts:284:16)
at Function.login (server/lib/ldap/Manager.ts:53:11)
at packages/accounts-base/accounts_server.js:593:9
at tryLoginMethod (packages/accounts-base/accounts_server.js:1560:14)
at AccountsServer._runLoginHandlers (packages/accounts-base/accounts_server.js:592:22)
at AccountsServer.Accounts._runLoginHandlers (app/lib/server/lib/loginErrorMessageOverride.ts:9:17)
at MethodInvocation.methods.login (packages/accounts-base/accounts_server.js:654:22)","isClientSafe":true,"error":403,"reason":"Email already exists.","errorType":"Meteor.Error"},"msg":"Email already exists. [403]"}

It looks like RC is trying to create a new user but it fails because of the email beeing the same of the prévious user (prévious username).

What can I do to handle that problem ?

Steps to reproduce:

1. Connect RC to LDAP
2. Sync or connect with one of the user to create the RC user
3. Modify the username in LDAP directory
4. Try to connect with the new username

Server Setup Information:

• Version of Rocket.Chat Server: 7.5.1
• License Type: Community
• Operating System: Debian

Client Setup Information

• Desktop App : 4.3.3
• Operating System: Windows 10

Start with server/lib/ldap/Manager.ts, especially the login, addLdapUser, and syncUserForLogin entries, then follow server/lib/ldap/UserConverter.ts and app/importer/server/classes/converters/UserConverter.ts. Reproduce the username-change steps and trace the existing email handling; done means the renamed LDAP user is handled without creating a conflicting account or producing “Email already exists.”