# Troubleshooting LDAP Authentication

Error | Possible Cause | Corrective Action
"Failed to contact server(s)" | Mitel Certificate Authority (CA) is not installed on directory server. | Install Mitel Certificate Authority (CA) on directory server. Then, you must reboot the directory server.
Cannot enable LDAP Authentication | SSL/TLS not enabled on MiCollab | Ensure SSL/TLS is enabled on MiCollab. See Configure LDAP Authentication.
SSL/TLS not enabled on directory server. | Ensure SSL/TLS is enabled on the directory server.
MiCollab SSL/TLS port settings don't match those on the directory server. | By default, MiCollab IDS uses port 389 for TLS and port 636 for SSL. These defaults are also used by Active Directory. If Active Directory is using different ports, you must change the SSl/TLS port settings in the Manage IDS Connections form to match them. To determine if Active Directory is listening on a specific port, enter the following command from the MiCollab server console: #> telnet <your AD IP> <port #> Example: #> telnet 10.45.102.88 636