Hello, I am trying to setup a new VoIP provider on my 3CX v12 PBX, it registered ok but when i tried to do an outbound call i took these error: Call or Registration to number@(Ln.10000@Provider_1) has failed. [ V4 Provider_IP:5060 UDP target domain=unspecified mFlowKey=800 ] replied: 403 Forbidden; from IProvider_IP:5060 and other times: Call or Registration to Provider_Name has failed. sip:username@provider_hostname:5060 replied: 403 Forbidden; warning: Invalid User; from IProvider_IP:5060. On 'remote connections' the status is Registered and if i make a registration refresh it registers ok. Also i tried to connect this provider directly to a sip phone and it works with no problems. What is wrong? I have many others VoIP providers on my PBX without problem. Is it an incompatibility with 3CX or something else? Thanks!