I've tried to provision some 3CXPhone clients as extensions on the local LAN, and am having a problem with them registering for Presence when on our LAN network. Here's the situation, w/ 3CX Phone: When on LAN / In Office set: Phone works > "On Hook"; Presence "Not Connected" When on LAN / Out of Office set: Phone works > "On Hook"; Presence "Available" When connecting remotely: Phone works > "On Hook"; Presence "Available" The weird thing is that when I delete this configuration on 3CXPhone and enter everything manually by hand. Everything works ok! It appears 3CXPhone doesn't even try to make an attempt to connect when on LAN/"In Office" I'm thinking this may be a possible bug? My workaround is to do all config by hand; does anybody have any suggestions? FWIW, I have tried modifying the configuration here and there, and re-connecting - but at the moment, the only way to get it working again is to delete the entire entry on 3cxphone, and input manually, then reconnect. I should mention that the way I am provisioning the 3CXPhone is having the 3CXPhone turned on and app open, goto 3CX admin > Phones > [click on entry of corresponding 3CXPhone] > Click setup as New Extension at top; following this, 3CXPhone would automatically configure. One strange thing that I do get from the auto configuration is that the 3CX admin console says: "An exception occurred EditExtension Error: The remote certificate is invalid according to the validation procedure."; however the 3CXPhone is otherwise configure and working for calls.