Hello, Yealink T42G, latest firmware. Disallow use of extension outside the LAN is unchecked as required (remote site, connected via site to site VPN). I have been able to provison 3 handsets manually but further devices are showing as 'register failed'. The account details are all correct, I've lost count how many times I've checked everything but all looks good. The handsets even have access to the 'remote phone book' so some sort of provisioning has taken place. I've reset passwords, user accounts etc. I'm absolutely stumped... Any idea's?