Hello, I've set up a new 3CX server recently (debian). I'm working thru several problems with it, but this one is most annoying: As soon as the 3CX Phone application goes out of focus, or screen turns off, the application disconnects. And since it is running trough the tunnel, other SIP applications (zoiper, ekiga) won't even connect to the server. This is not limited to a certain phone, but all android devices I tried it on. Just to follow the rules, here is the phone information: APP_VERSION:150141 PACKAGE_NAME:com.tcx.sipphone14 PHONE_MODEL6603 ANDROID_VERSION:6.0.1 BRAND:Sony PRODUCT6603 The server version is the latest one, and fully updated. 3CX Phone System Standard Edition Version Number: 15.5.5 It has a static public IP address. The server sits behind a mikrotik router, and has all the rules created according to the instructions. The firewall check comes up as "Firewall test OK". The only difference from the vanilla setup is the SIP port moved from 5060 - all firewall / nat rules are changed accordingly. The Push service is set, but it is not working. I've tried with the "own" account (followed the instructions), and later on switched back to "3CX Account". I've re-provisioned the phones after every change made. While running in the foreground, it can call out and receive calls. Help ?