Communication Problem with Cisco IP Phones CP-3905

[patsonzero]

Good evening everyone,
I implemented a TOIP network in a small company in which I used the following equipments: Cisco IP Phone CP-3905, a Cisco SF200-24P switch, and a Cisco 2901 (CME version 15.3 ) IPBX . Initially, communication worked well between all the users. But for a while, to contact some users, you have to call them 2 or 3 times before the call passes. Currently I do not know where the problem is.
Can someone help me solve this problem?
thank you in advance

[Maren Mahoney]

Can you describe in more detail the behavior you mean when you say " before the call passes"?

For instance, do you mean that users are unable to get dialtone when they pick up their handset? Or User A must dial User B more than once before it will ring on User B's phone? Or that User A calls User B and User B picks up but the call does not connect? Are callers getting busy signal, fast-busy (reorder tone), dead air, no ringback tone, etc.?

[patsonzero]

Hi,
Here is the detailed description: "User A must dial User B more than once before it will ring on User B's phone".

[Dennis Mink]

is this issue between users that use phones registered to the same CME?  or across PSTN?

[patsonzero]

Hi,

The problem is between registered users who use the CME. Users are not connected through the PSTN.

[R0g22]

Interesting. Does this happen always or it is just intermittent ? When the call fails for the first time, what does the output for "show voice register pool all br" show ?

If it is easily reproducible, take logs for "debug ccsip message, debug voice ccapi inout and debug ccsip error" for a failed call. Attach your config as well.

[Joel Fox]

So it's dead air or doesn't establish at all? Do you ever get voicemail when the call fails to establish?