Our customer is now saying that we are not adding a space in the Call-ID. They have space at the beginning in the invite and when we reply with trying the space is not there and their Cube does not recognize it. How to solve this?
Space or no space are both valid to the Spec.
And, we have an option to add space via Web portal → SIP → Quirks → Generate Space After Colon. Enable it and activate the configuration. Then you will have space before the Call-ID.
Can I create a new sip and setup their sip servers under that sip?
There will be only one SIP stack, but you can create different SIP Transport server dedicated to one interface/NAP.