I come across an issue within a CUCM 10.5 environment with a 7945/65 IP Phone. The UC Cluster has a range of phone models varying from 7940/60s to 8851′s.

When the Phone Services button was pressed on a 7945 or 7965 IP Phone, the phone service subscriptions would list correctly, however the phone continued to request for subscriptions, the phone display would show “requesting…”, eventually timing out and displaying a “Host Cannot be Found” error.

However, if the phones services button was pressed on a 7940 phone, the phone service subscriptions would list and the request would complete. This was the same for 7941, 7942, 7962 etc.. Also the 8851 phones would also display the subscriptions correctly under the Settings Menu.

I captured the packets between the 7945 IP Phone and CUCM to see what was going on. The phone was sending a secure request over port 8443. However in the Enterprise Parameters page, the secure URL for Phones Services was entered as http:// and not https://. Normally this would fine except the tcp port also entered was 8443 and not 8080 (non-secure). I changed the Secure Phones Services URL to https:// and the 7945 and 7965 IP Phones would then display the correct Phones Services subscriptions and the requesting service would complete with no errors.