New zulu user, unable to make any calls from mobile or PC soft phone


As more and more users work from home I have been looking at setting up zulu for them but can’t get it to function.

Background: Our PBX (version has been up and running perfectly for many years now with no issues and I’ve made sure all modules are updated to the latest versions. It is hosted in the cloud and has a static public IP address with no NAT or other firewalls to block anything. I typically use iptables to whitelist IP addresses that need to connect but for troubleshooting purposes have turned off iptables so there is nothing to block any connections or ports.

The initial issue I had is neither the PC or mobile app can make any calls, either internal or external. The PC app simply gives a fake ringing tone but doesn’t actually call anything while the mobile app sits at “connecting call” and fails after about 30 seconds.

After reviewing the asterisk logs while attempting a call I could see my mobile phones private LAN IP address was showing up in the logs (eg 192.168.1.x). Upon disconnecting my phone from wifi and using just the cellular connection I was then able to at least initiate a phone call and hear a ring tone, however the moment the other party picks up their mobile phone the zulu app crashes. If I call my own internal extension from the mobile app I get my voicemail and can leave a message indicating that 2 way audio is at least working when the client side is not behind NAT.

Based on this I looked for NAT settings for pjsip but there don’t appear to be any, under CHAN SIP settings there is a “YES ALWAYS ASSUME NAT” option but there doesn’t appear to be any such similar option for pjsip.

How can I work around the NAT issues with pjsip and is there a known issue/fix for the mobile app crashing as soon as the call is connected? I saw a support article here but it didn’t go anywhere:

It’s worth noting that I exclusively use chan sip for our 50 desk phones and it works fine, I only enabled pjsip just now for zulu.

Hey Mike,

Zulu Mobile is not supported on FreePBX 13 … for debugging those NAT issues (assuming you have those on your desktop client) you should open a support ticket as they are more qualified and they will be able to use tools to determine what is the specific issue here.


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