We have a setup of the latest Multi tenant, using Yealink T22 phones. The problem comes and goes where if someone calls in, the ring group dials all the handsets in the group, when someone pick up the phone there is a 4-5 second delay before the call is actually connected. Its not an audio delay, where the call is connected and it dead air for a few seconds. When you pick up the handset, the phones show is still ringing, then after 5 seconds you see the call timer start and you know the call has connected. The same happens dialling out. Pickup, dial the number and 5 seconds later the call starts to connect. This is a hosted system so all extension are 'external'. The handsets are setup to use the 3cx stun. There are no issues with audio. Everything works perfectly, apart from this delay. Anyone have any ideas what might cause the delay?