Description:

Upgrading from v3.5.4 to v3.6.0 results in LDAP users not able to log in : the error popup "User not found or incorrect password" is displayed.
Local users are still able to log in.

Steps to reproduce:

1. Go to login screen
2. Enter LDAP username and password
3. Click [Login] button

Expected behavior:

User should be logged in, as in all previous release versions up to v3.5.4.

Actual behavior:

Error popup : "User not found or incorrect password"

Server Setup Information:

• Version of Rocket.Chat Server: 3.6.0
• Operating System: CentOS 8.2.2004
• Deployment Method: tar
• Number of Running Instances: 1
• DB Replicaset Oplog: yes
• NodeJS Version: v12.18.3
• MongoDB Version: 4.0.3

Client Setup Information

• Desktop App or Browser Version: Firefox 80.0
• Operating System: Linux Fedora 32

Additional context

• Having successfully upgraded today through releases 2.4.11 -> 3.0.0 -> 3.0.12 -> 3.1.3 -> 3.2.2 -> 3.3.3 -> 3.4.3 -> 3.5.4, this issue exhibits itself exclusively on the latest release 3.6.0.
• The LDAP user/password lookup query returns no errors (cfr. logs).
• The LDAP Synchronisation yields an error (cfr. logs) : error: 'file-too-small'

Relevant logs:

Please find relevant logs (potentially sensitive data obfuscated) in attachment.
(Log_level=2 , LDAP_Internal_Log_Level=info)

Debug log sections :

• Admin > LDAP > [Test connection]
• Admin > LDAP > [Execute Synchronization Now]
• LDAP login (with valid credentials)

For comparison, the following debug log sections were also added :

• LDAP login (invalid password)
• LDAP login (invalid user)
• Local user login

RC-3.6.0_LDAP_login.txt