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Voicemail is randomly busy for random users


Good morning, I have inherited a Cisco Unified CM phone system unfortunately I have little knowledge about these systems. My issue began about a month ago, with a few users calling to tell us when they call their voicemail they receive a busy signal, if they hang up and try again, they will get the same thing for about 30 seconds, and then it will work again for them for an indeterminate amount of time. There is also reports of customers being hung up on instead of call trees being activated when they call.

Our setup includes:

2 cucm servers, 2 cuc servers, 1 cups server
cucm -
cuca -

Some things I have tried include restarting the phones, restarting both cucm servers, one after the other, the same with the cuca servers, one after the other. Also rebooted the cups for good measure after those four. I had a few users that were registering with the wrong cucm, got them all to the same cucm server. I'm not really sure what else to try, but if anyone has some suggestions that would be awesome! Thanks for all the help.

3 Replies 3

Les Pruden

It sounds like you might not have enough voicemail ports. You can monitor the voicemail ports using RTMT or Port status Monitor Connection 7x (Home ( If you are running SIP trunks between CM and CUC you can add ports in CUC. If you are running SCCP ports between these systems, you will have to add new ports in both CUCM and CUC.

System Administration Guide - Telephony Integration [Cisco Unity Connection] - Cisco


Thank you so much for the reply, this answer sent me down a few rabbit holes and it does look like we may not have the licensing capacity. I talked to a friend with a little more cisco knowledge with me and he recommended cleaning out some of the old numbers and voicemail boxes that are unused in the system. I am going to give this a try and see how it goes. Have a wonderful day.

Voice mail ports are not licensed.

the voicemail ova define the capacity of voicemail ports. If you are running a 1000 user BE6k deployment each cuc server support 24 ports so in total you can have 48 ports.

check on cuc the number of ports configured.

i feel it’s due to the ports usage you are getting  busy 


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