Secure phone communication error

[mjack103]

I have secure phones that voice/audio  works fine. However, when I go secure it fails. the  modem train doesn't complete and a communication error appears. On a regular phone line, they work good. However, I get this error when I used the lines coming off of the CISCO VG-310 Gateway. Is there some setting on the VG310 that could be causing the modem train not to connect on my secure phones? 

[Roger Kallberg]

What do you mean by “modem train”?

This document describes how to setup secure signalling and media on a VG224, as this is very similar to a VG310 it should be applicable.

https://www.cisco.com/c/en/us/support/docs/unified-communications/vg-series-gateways/212138-Configure-VG224-SCCP-Secure-Encrypted.html