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Telephone service is unavailable- Cisco 9971 with CME 10.5

Hi All

I have 2 Cisco 9971 IP Phones.  They were registered with CME 10.5 [2901/IOS Version 15.4(3)M3]. These two phones were working fine until I configured the Intercom button. As soon as I assigned the Intercom button they keep restarting and showing the message "Telephone service is unavailable"

The following is my configuration.

voice register global
mode cme
source-address port 5060
max-dn 10
max-pool 5
timezone 31
date-format D/M/Y
tftp-path flash:
create profile sync 0119269186207239
ntp-server mode directedbroadcast

voice register dn 1
number 1001

voice register dn 2
number 1002

voice register dn 3
number A100
intercom speed-dial A101 label Assist

voice register dn 4
number A101
intercom speed-dial A100 label Manager

voice register pool 1
id mac 10BD.18DC.9577
type 9971
number 1 dn 1
number 2 dn 3

voice register pool 2
id mac 5897.1ECC.ADFC
type 9971
number 1 dn 2
number 2 dn 4

Please help. 

VIP Advisor

Did you try to removr the intercom, create profile and reregister the phones. Try it to see if they will work again.

Also, try to get debug ccsip mess during restart


Hi Mohammed

Thanks a lot for your reply. Yes I did remove the intercom. And the phones registered and working fine. In the debug i could see a lot of REFER messages coming. I couldn't get why the phones are sending a lot of REFER messages. 

Attached the Logs. Please check it. Thanks a Lot

Abdul Rasheed



These refer messages are sent from IP Phone to CME to notify about the reason for last reset. I can see that LastOutOfServiceReason is 14. This means that CME dropped CME connection.

Not sure why CME drops the connection with intercom. I am not aware about a bug similar to this (still can be the case)

Not sure how easy it is to change the IOS but worth trying it. Please give it a try with new IOS and let me know how it goes. I don't see problem with config except that you are missing auto-answer command under the DN.


Hi Mohammed,

Thanks a lot for your reply. I noticed the REFER messages. I cannot update the IOS now as I don't have the access to cisco IOS download now. Once I update the IOS i will check the configuration again and I will inform you the result.

But I need another help from you. As a part of my troubleshooting i was going through some debugs. Here is the scenario. I have 2 Cisco 9971 IP Phones registered to CUCME (10.5).

I call from 1212 to 1010 (extensions of 9971 phones) and hung up from 1212. The BYE message is showing the proper direction. But when I made the same call and hung up from 1010 (the called party) it is not showing that the BYE message is extended to the Calling party (1212). I have attached the log files and ladder diagram generated using TranslatorX.

Thanks a Lot for your Time