LDAP user can not login after db update from 4.4 to 5.0

Description:

After db update from 4.4 to 5.0 LDAP user can not login neither to WebUI nor app – got WebUI crash error.

Steps to reproduce:

1. stop rocketchat
2. stop mongodb
3. change mongodb compatibility settings
4. update mongodb from repos
5. start mongodb

Also

• checking LDAP connection from UI works
• finding LDAP user from UI works
• local user login works

Also did not help:

• mongodb export and import after update (with indexes)
• clear indexes
• clear banner settings for user

Actual behavior:

Got UI crash error.

Server Setup Information:

• Version of Rocket.Chat Server: 6.4.5
• Operating System: Debian 11
• Deployment Method: Manual installation
• Number of Running Instances: 1
• DB Replicaset Oplog: Enabled
• NodeJS Version: 14.21.2
• MongoDB Version: 5.0.22 wiredTiger (Single node replica set)

Client Setup Information

• Desktop App or Browser Version: Safari, Chrome
• Operating System: macOS, iOS

Additional context

New LDAP users can login

Relevant logs:

{"level":50,"time":"2023-11-08T08:28:45.040Z","pid":995,"hostname":"servername","name":"LDAP Data Converter","err":{"type":"errorClass","message":"Username already exists. [403]","stack":"Error: Username already exists. [403]<br> at AccountsServer.insertUserDoc (packages/accounts-base/accounts_server.js:1206:15)<br> at app/authentication/server/startup/index.js:301:28<br> at /opt/Rocket.Chat/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/fiber_pool.js:43:40<br> => awaited here:<br> at Function.Promise.await (/opt/Rocket.Chat/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/promise_server.js:56:12)<br> at AccountsServer.Accounts.insertUserDoc (app/authentication/server/startup/index.js:363:17)<br> at app/importer/server/classes/ImportDataConverter.ts:375:19<br> at /opt/Rocket.Chat/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/fiber_pool.js:43:40<br> => awaited here:<br> at Function.Promise.await (/opt/Rocket.Chat/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/promise_server.js:56:12)<br> at app/importer/server/classes/ImportDataConverter.ts:525:18<br> at /opt/Rocket.Chat/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/fiber_pool.js:43:40","isClientSafe":true,"error":403,"reason":"Username already exists.","errorType":"Meteor.Error"},"msg":"Username already exists. [403]"}

Start by reproducing the 4.4-to-5.0 MongoDB upgrade and inspect the LDAP login path in app/authentication/server/startup/index.js. Trace the Username already exists error through app/importer/server/classes/ImportDataConverter.ts and AccountsServer.insertUserDoc. Done means existing LDAP users can log in to the WebUI and app after the upgrade without a crash.