Product specifications

420HD IP Phone with Microsoft Lync
Administrator's Manual 14 Document #: LTRT-09930
2.3 Troubleshooting
2.3.1 Using the Phone LCD to Troubleshoot
Use the table below to help troubleshoot deployment problems that can occur after
preparing the enterprise network environment for IP phone deployment.
Tip: Use the first phone that you deploy as an indicator for the entire deployment. If
the first phone plugs in and plays without irregularities, all phones deployed
after it should also. If it doesn't, troubleshoot as shown in this section before
proceeding to deploy the other phones.
Note: After preparing the network and verifying readiness, make sure that the Lync
PC client is operating, i.e., that the Lync server-client (Front End) setup is
correct. Only after this, deploy the first phone.
Table 2-4: Troubleshooting Deployment Problems
Problem / LCD Notification
Corrective Action
Certificate problem
LCD Notification:
"Failed to validate certificate" -or-
"Failed to obtain user certificate"
Three possible actions:
 Make sure that DHCP Option 43, sub-option 5,
was enabled in the DHCP server. If it wasn't,
enable it.
 Make sure you can access the Lync Web service
URL:
https://lyncsvrWebPoolFQDN:443/CertProv/CertProvisioningService.svc
 Query the LDAP server:
_ldap._tcp.<DOMAIN name>
Make sure it was enabled. If it wasn't, enable it in
order to get the root certificate.
Synchronization problem.
LCD Notification:
"Failed to connect to time server" -or-
"PIN internal error"
 Make sure that at least one of the following was
configured to enable synchronization:
 NTP server, via DNS SRV record
(_ntp._udp.<SIP domain>pointing to NTP
server)
 NTP server, returned via DHCP Option 42
 Time.windows.com
 Time.nist.gov
 Configuration Parameter (manually)
Phone not initializing
Make sure that DHCP is enabled.
Cannot find SIP server for 'Domain
name'. Phone can't perform registration.
LCD Notification:
"Failed to connect <domain> server"
-or-
"Cannot find Lync server at <>"
 Make sure that at least one of the following is
enabled in the DNS server:
 _sipinternaltls._tcp.<domain> (for TLS)
 DHCP results (Option 120) (for TLS)
 _sipinternal._tcp.<Domain> (for TCP)
 DHCP results (Option 120) (for TCP)
 _sip._tls.<Domain> (for TLS)
 _sip._tcp.<Domain> (for TCP)