Mobile devices with 3CX app can't receive calls

[Rick Ford]

Hello community,

We are a non-profit and have been using the free license for 5 years or so. It has now expired, but most of the features continue to work. (v18) I had to create a free cloud system (1460.3cx.cloud) to post, but it is not in-use.

We have an on-prem 3CX implementation that's been running for several years, moved to a new server April 2024. It was working fine with mobile devices with the 3CX app. Now, users can make calls from the app but not receive calls. Calls can be made and received on the desk phones and the webclient. It happens with ALL mobile devices, both Android and iOS. On my phone (Android) I have checked all the config options (PUSH notifications = ON on the phone and in the 3CX mgmt console for that user). I have registered my mobile phone on the same ext as my desk phone, and I've registered my mobile phone to a different ext without a desk phone. I can not get the mobile phone to indicate an inbound call. The failed call does show up in the phone's call history as a missed call. If the extension ALSO has a desk phone, then the incoming call will ring 3-4 times and then roll to voice mail, as designed. If the extension does not have any other phones, only the mobile client, then the call immediately rolls to voice mail.

I don't know when the problem started because we have very few inbound calls that we take on our phones. First reports from users came in last week (July 1, 2025)

On the mobile phone I have 1) cleared cache and data; 2) uninstalled and reinstalled mobile app (from Google Play); 3) re-provisioned the mobile phone on multiple extensions. Nothing works. I have tried with the mobile phone on WiFi and mobile data.

I have looked at the logs, but nothing seems to indicate the problem. I see what is a suspicious message to me: both the mobile client and the IP phone (Grandstream GXP) generate a "Device Not Identified" message, but the IP phone shows the correct IP address of the phone but the mobile client shows a 127.0.0.1 address. That may be normal--I don't know. (Note: the call comes in to the IP phone but not the mobile client)

07/08/2025 10:41:51 AM - [CM505001]: Endpoint Extn:36: Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CX Mobile Client] PBX contact: [sip:[email protected]:5060]

07/08/2025 10:41:51 AM - [CM503002]: Call(C:25): Alerting Extn:36 by contact <sip:[email protected]:5483/UDP>

07/08/2025 10:41:51 AM - [CM505001]: Endpoint Extn:36: Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [Grandstream GXP1625 1.0.7.13 c074adc269ea] PBX contact: [sip:[email protected]:5060]

07/08/2025 10:41:51 AM - [CM503002]: Call(C:25): Alerting Extn:36 by contact <sip:[email protected]:5060/UDP>

Any ideas? I have complete access to my phone (Android) and the 3CX environment, but very limited access to any of the iPhones in the office.

Versions:
PBX
OS: Debian 10 "buster"
3CX: 18.0 Update 9 (Build 35)

Android
Phone: Pixel 8 Android 15
Mobile Client: Version 5.1 (Build 41) 20.3.0.41

SIP Trunk
Deutsche Telekom (CompanyFlex - VoiceData)

Location: Germany

 

[KyriacosS_3CX]

Hello,

Please move to a newer 3CX version.

Best,
KS.

 

[Rick Ford]

Hello KS, thank you for your very quick response. If I understand correctly, I am not able to upgrade to v20 with a free license and on-premise, or self-managed, installation. In the management console the UPGRADE link tells me that my subscription is not valid. I have installed v20 on a test system and, from what I can tell, I can get only a 1 month trial license. I don't think I can move to a newer 3CX version and still be on-premise and free. My interpretation of the 3CX announcements is that they no longer offer a free license for on-prem, only for hosted. But, if I don't understand it correctly, I would love to be updated.

thanks,
Rick

 

[KyriacosS_3CX]

Hello,

You are correct that currently the Free version is Hosted by 3CX only.

Is there a hard reason why you need on-prem? Perhaps the community will have some ideas about how to switch you to cloud with your needs taken care of.

Best,
KS.

 

[bitn2]

You missed the timespot to upgrade to v20 with your free licence. Now you need to switch to hosted to use a free version. v18 wont work with mobile phones anymore. With a company flex plan you can switch to hosted without problems.

 

[Rick Ford]

Thank you @KyriacosS_3CX and @bitn2 I certainly appreciate your very quick responses. I have 24 users currently on my on-prem installation. Our volume is extremely low--1 or 2 calls per day, both inbound and outbound. The free hosted version allows only 10. I fully intended to upgrade to v20 last spring before the deadline, but had some health issues that prevented it. Not 3CXs fault, of course. So, I'm stuck. As I see it I can:

1) stay with what I have and live without inbound calls to mobile app;
2) try to consolodate the user community down to 10 and use the free hosted;
3) pay the 350/year fee for PRO;
4) move to a different platform.

Can you think of any other options? Do you know if 3CX has any discounted pricing for non-profits in Germany?

I fully understand that 3CX is in business to make money, thus the changes in their pricing model. I don't fault them at all. As a non-profit I just don't have the budget.

thanks,
Rick

 

[bitn2]

You already mentioned your options... One could be also a solution, find a partner who is offering the new multi tenant version of 3cx. There could be a way to stay on 3cx with less cost than a self hosted pro version.

 

[KyriacosS_3CX]

Hello,

v18 will stop working in multiple ways around September, so staying as-is is not a long term solution.

I suggest you talk with a Partner who might be able to offer you good value as a shared user on a Multi-Company server.

You can browse partners here:
https://www.3cx.com/ordering/find-reseller/

Best,
KS.

 

[fortech]

Hi Rick, I think your summary a few posts up the thread kind of gets the path forward pretty clearly laid out / and btn2 reply re: maybe find partner who can do a slice on a multi-host box might be the best-only-3cx-option for lower price point.

I believe it is also the case, active partners may choose to sell you a 4SC license / this version is no longer available to buy 'directly' and is being ~sort-of-discouraged / with the 8SC license being the new-target-baseline (I believe). I believe there is a modest price drop from 8SC to 4SC (350USD per year for 8SC vs 250USD for 4SC for pro-tier product, I think).

Potentially your non profit might find that price point less of a barrier, although arguably both price points are pretty modest when considered in the context of "phone system for 24 users"

So, possibly a partner who is happy to work with you / who is possibly local to your geography / and willing to do a slice on a multi-tenant box - may followup to this thread.

possibly you can carve down your user base to get to 10 active users only, and then you are OK to use 3cx on the 3cx-hosted-free-edition.

or then you are left to consider making plans for a different phone system. Or trying to convince someone who controls budget, about the value of a good phone system with nice smartphone integration etc. and possibly considering a bit more $spend for phones.

sticking on the current (kind of broken, and likely to get more broken ~soon - september) - is really not a great solution - so probably some kind of change is necessary "in graceful manner ideally" maybe.

Tim

 

[Rick Ford]

Thanks everyone for your suggestions and input. I do greatly appreciate it.