Mobiles Unable to Connect to 3CX Application on Internal Network

[RESOLVE-WR]

Afternoon all,

Please could you help with the below query?

- A customer we hosts laptops and workstations can connect to 3CX OK over the internal work Unifi Wifi.
- Android phones can connect to 3CX OK over mobile data and over home Wifi's but cannot connect over the internal work Unifi Wifi.
- We can see traffic going between a mobile and 3CX on port 443 over the firewall but nothing else happens.

The System I've chose isn't the one effected, but I'm currently obtaining that information.

Has anyone else has seen this? Or are their any ports we need to open? Thanks!

 

[SteveITS]

Typically internal devices won’t connect through the firewall unless NAT reflection/hairpinning is used…any ports used would need to be forwarded. 3Cx recommends split DNS which will be required at some point: https://www.3cx.com/docs/creating-fqdn-split-dns/

 

[leejor]

3CX is hosted externally? If that is the case, then any extension is considered remote.You say that in a number of scenarios, devices are able to connect just fine, which suggests that the port configuration at the 3Cx end is working as it should. Is it just at one location (as far as you know), that devices do not seem to be able to reach the 3CX server?
Have you checked the 3CX Activity Log, for clues as to what might be happening when one of these extensions attempts to register?

Since you seem to be talking about mobiles, I assume that they are using the tunnel port. Could that be blocked? Firewall issue?