SCCP phone registration works, but not SIP

[simc92]

Hi,

I am facing an issue at a remote site where the 7941 phones are registering successfully with SCCP, but the 7841 phones are not registering in SIP.

Here are some error messages (we have a CUCM publisher and a subscriber):

"Unable to get next ccm!"
"CC <PRIMARY_CCM>: connection already closed"
"No active CUCM found using primary CUCM" "CUCM A.domain.com Not connected"
"reg all fail, not failover"

The SIP phones are able to obtain their IP addresses and the DNS and TFTP are working well.

We have a Cisco gateway (2901) which acts as a DHCP server for the phones.

It is connected to a router with a data VLAN (with NAT) and a voice VLAN.

I initially thought that it might be due to the SIP ALG, but the NAT is only active on the data VLAN.

Do you have any suggestions?

[Nithin Eluvathingal]

If phone communicate with CUCM through a firewall disable SIP inspection.

2.12.0.0

[Roger Kallberg]

Can you please outline your network topology so that we can better understand how your connectivity looks like? Based on your description it would seem like a probable cause could be that the phones are not able to communicate with the CMs on port 5060 (SIP). Check that you allow both TCP and UDP on this port between the phones and the CMs.