Hi, I've a few questions around this issue : - I've installed Elastix 5 on a test machine, that test machine has normal access to the internet like all other machines in our network - we have a secured and strict DNS infrastructure. - all LAN machines have access to our internal DNS, which in its turn has amongst others, the google DNS as upstream. - no machine is allowed direct access to outside DNS servers on the elastix test machine, all normal (OS level) DNS tests pass, and a check from that machine, does resolve your servers : (your ISO build is missing the nslookup command) erp.3cx.com (18.104.22.168) activation.3cx.com (22.214.171.124) So the questions are : - why do I still get the license error? - why is your software forcefully trying to bypass our internal DNS servers, and try to use Google DNS ? -- a tcpdump seems to explain that your software only queries the google dns servers for activation.3cx.com, and when there is no answer from Google DNS, the whole process stops - even adding activation.3cx.com to the hostsfile with the correct IP does not work. Can you explain why Elastix5 is behaving like this? L.