Hi there. I have an Epygi ISDN gateway set up in our office. We have inter-branch calling set up over voip to our branch office. the branch office is using an asterisk server. eg. If I dial 5407 this calls an extension at the branch office and vice versa. This was working until recently. Our office is unable to dial the branch office, but they can dial us. All I get is "number dialled temporarily unavailable". I'm not sure where to start troubleshooting this. No changes were made to the pbx. Could anyone point me in the right direction please?