W52P - Extension Dialing Issues

[jolouis]

Agree with Craig on this one it's almost always a firewall issue for those kind of strange call behaviors. Contact your Cloud PBX provider, let them know what firewall (OR DSL modem if it's an integrated modem/router/firewall) you're using and they should be able to provide you support or point you in the right direction. If not, then the next step would be to contact your ISP or whoever provided the firewall/modem/router and have them check to make sure everything is OK.

Many of the integrated modem/routers for small office/home use have strange built-in filtering and "SIP ALG rules" that are supposed to somehow make things better but almost always just break things in strange and unexpected ways. Typically you need to disable those features to make things work properly. Do a quick google for "SIP ALG" and you'll see what I mean...