Change 'Internal IP' for phone apps

[FOEngineering]

How do I change the internal phone "IP" to not use the FQDN.
We have an internal, non-broadcasted wifi, that we cannot allow personal phones to connect to and it uses the same IP range, 192.168.30.0/24. We then have a Wifi guest network that we can connect our personal devices to, 192.168.40.0/24. The phone app works great, everywhere except in the shop. We can receive calls, but cannot connect or call out.

I can create a IP pass-through to the 3CX server on the guest network, but the changes I have tried to make to the to "Parameters" have not translated to the phone app.
Where can I make the changes?

Thanks ahead of time.

 

[SteveITS]

If I followed, the correct way to fix this is to use split DNS or NAT reflection: https://www.3cx.com/docs/creating-fqdn-split-dns/

Then devices all use the FQDN and HTTPS.

If the apps were set up using an IP or HTTP, to change them they need to be set up again. (delete account within the app and re-add)