If you are using unsupported voip providers do not base on the colors you see in the management console. Apart from the fact that IP Based trunks show green by default since there is no registration, so there is no communication therefore there is no state.
You need to make a call, wireshark it.
Then you can give details here or you can to to DIDWW, show them the capture and ask them "Why is it theoretically failing?"
He might tell you because we dont trust the ip, or 3CX is sending this in the wrong sip field place. Come to me and I will tell you what to do.