Greetings, I am working on a new 3cx installation. I'm having a problem where all extensions are constantly registering/unregistering (this includes system extensions). I'll start the server up--everything will look good. I was able to briefly have a conversation between 2 extensions. But when I tried to call back between them, one of them had unregistered. A moment later both were unregistered. My system extensions are doing the same thing, they constantly fluctuate between registered and unregistered--not all at once, but one at a time. Each refresh of the screen shows different extensions (phone and system) registered. Essentially my extension status panel is blinking like xmas lights. 3CX is running on a Hyper-V VM. There's a dedicated NIC in the host for the PHONE network (which also gets it's own port on the router--a Ubiquiti ER-Lite). There's a subnet setup for the phone network and a dedicated switch to connect it all together. No problems showing with network connectivity (I can ping between phones and 3CX VM continously with no dropped packets). I can make outgoing calls from an extension while it is registered. Generally if I go to the provisioning page and hit save, the extension comes registered for a little bit (couple minutes). Anytime I try to receive an outgoing call to an incoming extension, the extension immediately goes unregistered and the call goes to 3cx voicemail. I've tried deleting the VM and starting over with a new installation multiple times and the same issues persist. The phones are Yealink T46S and T42S's (all extensions experience the issue). They were auto provisioned by 3cx. Firewall test passes. Anyone have any ideas? I'm beating my head against this one. Thanks!