Why am I getting an "Invalid Login Credentials" error on my LDAP server?

Linode Staff

When trying to log in or connect to my email's address book, I get an error stating "Invalid Login Credentials". What's going on?

1 Reply


1) Check to make sure that LDAP is currently listening on this Linode. From the terminal, a tool like nmap can be used to check this. LDAP is commonly assigned to port 389, but keep in mind that it may be configured on another port. This example uses the standard port 389:

nmap -p 389 123.456.789.10

389/tcp open  ldap

If the state displays “open”, then LDAP should be available. If it is “filtered” or “closed”, it may not be listening, or there may be firewall rules in place preventing access.

2) If LDAP is listening, but authentication still fails, this may indicate a problem with the user’s password. First, double-check to be sure that the correct credentials are being provided.

If you are absolutely certain that the credentials are correct, then the user may have a password that does not meet the requirements for your LDAP server’s password policy. For example, it may contain characters which are invalid under the current policy such as “\” or “:”. The system administrator will need to update the user’s password, or the password policy itself.

Below are links with more information about setting password policy for common LDAP servers:


Oracle Internet Directory

Microsoft Active Directory

3) Other issues may include a user’s account or account password being expired, or a misconfiguration on the LDAP server causing it to return more than one record for a single user. A system administrator will need to check the LDAP server’s error logs to diagnose the precise cause of the issue.

Below are guides with more information on troubleshooting common LDAP credential issues:

Pexip: Troubleshooting LDAP server connections StackOverflow: Enter LDAP Password keeps saying ldap_bind: Invalid credentials IBM: Common LDAP authentication errors


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