We have been having this issue on a handful of Balance series routers 20/20x. The WAN will go offline and the SIP phones will not recover. This has happened on multiple types of SIP phones. I have run a capture and can see the LAN sending registration packets to the WAN IP, but the WAN capture has no record of it. Rebooting the Peplink will bring all the phones back online. Has anyone else run into this issue and can offer a fix for this?