We have OTM setup at a central site with three other sites that are connected to OTM. Sites 1 and 2 connect fine, however I cannot connect to site 3. This has worked in the past but now it has stopped working. I cannot ping the remote PBX through the OTM server or vice-versa. However I can ping the remote PBX from the central site's Cisco switch. Does anyone have a suggestion on where to look next.