I have been having issues when I try to add a generic SIP trunk to an existing configuration with updated firmware. The trunk will register and receive calls but I cannot make calls out. I get a 604 does not exist error when calling out. The SIP trunk is from Simple Signal and when using the generic SIP trunk template on the UC config, it is missing the domain field. According to Simple Signal support this is a required field. When I tried another UC which has an older firmware, I noticed that the domain field was an option during the initial configuration wizard. After configuring this, the UC registered perfectly and was able to make calls out. Does the new firmware take away the option to add the sip trunk domain?
