[Resolved] Fongo Not Working on iPhone 16 Pro (iOS 18.1) on Telus Mobilty cellular Data with eSIM

[Itzmeeee]

Anyone having issues in the Vancouver area getting Fongo to work on cellular data? I recently upgraded from an iPhone 12 pro max to an iPhone 16 pro, and Fongo is the only app not working right. I'm on Telus Fibre home internet and a Telus cell plan.

My 12 works normally, but on the 16 Fongo keeps giving a red connection error retry message while on Telus cellular data. It works just fine on wifi. On cellular data the only way I can get Fongo to work is to use a VPN.

I've tested other free VOIP calling apps, and they work fine on cell data. I don't know what the issue is, but I suspect Fongo and iOS 18.1 have some sort of issue on cell data, but then again it works on wifi and VPN cell data which is bizarre!

[Liptonbrisk]

I'm using iOS 18.1, and I'm able to test on Telus Mobility. I'm not in Vancouver though or testing with an iPhone 16 Pro.

Visit https://support.fongo.com/hc/articles/2 ... ion-Failed
Do any combination of those settings help you?


Having all 3 settings off produces "Fongo Connection Failed - Click to Retry" error message for me.

Having just the "Allow IPv6 Connection" setting enabled (not the other two settings shown in the link) fixes the "Connection Failed" issue for me on iOS app version 2024.11 when using cellular data with Telus Mobility. For clarity, having "Allow IPv6 Connection" enabled is the default with both "Alternate DNS Resolver" and "Alternate Fongo Connection" settings being off.

These settings are found under Account-->Settings-->Troubleshooting.

Ensure that "Alternate DNS Resolver" is disabled. Having "Alternate DNS Resolver" enabled in conjunction with "Allow IPv6 Connection" produces that error as well.

After making changes, restart the app.

[Liptonbrisk]

My 12 works normally

Is it not using iOS 18.1?

I suspect Fongo and iOS 18.1 have some sort of issue on cell data

If your iPhone 12 Pro Max is using iOS 18.1, then I doubt iOS 18.1 matters. I'm using iOS 18.1, and Fongo Mobile works for me.

but then again it works on wifi and VPN cell data which is bizarre!

VPN will use different DNS servers, different routing, and possibly IPv4.
I'm not sure if you're using IPv4 on Wi-Fi (probably not). Routing and DNS for you should be similar on Telus home internet Wi-Fi as it would be on Telus Mobility cellular data.

Anyway, try https://support.fongo.com/hc/articles/2 ... ion-Failed to see if doing so makes a difference.

Lastly, while testing, ensure you're not using attempting to use same Fongo Mobile account on multiple devices simultaneously: https://support.fongo.com/hc/articles/2 ... le-devices. I doubt this is related to your issue, however.

[Itzmeeee]

Hey thanks very much for your help! I only have one sim card and using one phone at a time. I think the iPhone 12 is on an earlier iOS version. I'll check out those links as I've already tried default and various settings.

TextNow and TextMe work fine on Telus cellular data so it's very puzzling.

[Liptonbrisk]

I am unable to reproduce the issue at default settings using Telus cellular data on iOS 18.1, and since there’s no log file to look at, there’s not much else I can do.

You can submit a ticket for your issue here:
https://support.fongo.com/hc/requests/new.

—
Visit https://status.fongo.com/.
If "Support System" indicates "Partial Outage", ticket response time can take up to a week (or longer).


You can check your ticket status by logging in at
https://support.fongo.com/hc/requests. That's an account for tickets
(zendesk) only and is completely separate from your Fongo Mobile account or any other Fongo account you may have. If you don't have a zendesk account yet, click "Sign Up" after visiting the link.
Use the same email address that you use to submit tickets. Do not use the same password as your Fongo Mobile
account. Again, these accounts are all unrelated.

Support staff does not respond to tickets on weekends or Canadian holidays.
Support hours are 9 a.m. until 4 p.m. EST. They are not obligated to respond
on the these user-to-user support forums.

Volunteer moderators don't have access to anyone’s account and don't work for Fongo.


Fongo does have https://twitter.com/Fongo_Support. I'm not sure if anyone
there responds to direct messages.
Similarly, they appear to be on Facebook:
https://www.facebook.com/FongoMobile/. I don't know whether they'll respond to you there.

[Itzmeeee]

Thanks again for your assistance. I did try changing the various settings, reseting network settings, moving my sim card back to the 12 to test (which worked fine on cellular data again).

Maybe something got glitched in the iphone to iphone transfer. The physical sim had been converted to an esim which was then transferred to the new phone. After finding out Fongo was not working on cell data while everything else was, I converted the esim back to the physical sim by entering my sim card's ICCID into the Telus app. That reactivated it so it could be used in the 12 again.

I wonder if reseting the 16 completely and doing a fresh transfer would work using the physical sim card. I might try that.

[Liptonbrisk]

That's interesting. I was going to start speculating about the network stack, but it makes no sense why all other apps work fine. If you find the physical SIM works fine while the eSIM doesn't, then I would suggest reporting your findings to Fongo: https://support.fongo.com/hc/requests/new.

[fguser100]

Anyone having issues in the Vancouver area getting Fongo to work on cellular data? I recently upgraded from an iPhone 12 pro max to an iPhone 16 pro, and Fongo is the only app not working right. I'm on Telus Fibre home internet and a Telus cell plan.

My 12 works normally, but on the 16 Fongo keeps giving a red connection error retry message while on Telus cellular data. It works just fine on wifi. On cellular data the only way I can get Fongo to work is to use a VPN.

I've tested other free VOIP calling apps, and they work fine on cell data. I don't know what the issue is, but I suspect Fongo and iOS 18.1 have some sort of issue on cell data, but then again it works on wifi and VPN cell data which is bizarre!

It looks like the IP address that you got ( with Esim ) is banned from Fongo ( only a guess - it works with VPN : different IP adress )

[Itzmeeee]

That's interesting. I was going to start speculating about the network stack, but it makes no sense why all other apps work fine. If you find the physical SIM works fine while the eSIM doesn't, then I would suggest reporting your findings to Fongo: https://support.fongo.com/hc/requests/new.

Okay will do. I'll send the IP address that doesn't work while on Telus cell data and the working one on Telus Home Fibre internet. If it's banned for some reason maybe Fongo can free it up? Thanks for the replies!

[Itzmeeee]

Interestingly enough Fongo is working again on Telus Cell data! I didn't get a chance to forward IP addresses, and it just started working again on the way home from work. Not sure if maybe the app or phone just needed to recognize the data transfer from wifi to cell or something. Will check again once at home.

[Liptonbrisk]

There was an iOS app update, version 2024.11.1, released 3 days ago that includes unspecified “bug fixes” and “performance improvements”.

Perhaps 2024.11.1 contains the fix.

[Itzmeeee]

Ah I gotcha. All is working good so case closed! Thanks for your help!

[Liptonbrisk]

Thanks for letting us know and for reporting the problem to Fongo!

[Itzmeeee]

Spoke too soon - it stopped working on Telus cellular data. I'm on iOS 18.5, and I can confirm in Vancouver and Calgary Fongo won't connect to the server unless I have a VPN turned on. I wonder if Telus Mobility is blocking VOIP for some reason.

[Liptonbrisk]

Well, it’s 6 months later. Possibly Telus is upgrading something in your area, but it would surprise me if they’re blocking the ports Fongo Mobile uses on purpose.

Latest iOS App version is 2025.7. I'm on iOS 18.5 as well, but my comments are the same as last time.

Try the settings at https://support.fongo.com/hc/articles/2 ... ion-Failed, and try submitting a ticket: https://support.fongo.com/hc/en-us/requests/new.

[Itzmeeee]

Thanks for your help once again. I tried all the setting options one at a time, but it didn't work. I actually had to go into settings, cellular, cellular data network, reset settings there, and go into Fongo to enable Alternate DNS Resolver which made it work again. Very weird! Oh well I'll monitor how stable it is and also see if it works in Vancouver.

[Liptonbrisk]

I’m glad it’s working for you at the moment.

[Liptonbrisk]

I actually had to go into settings, cellular, cellular data network, reset settings there,

Basically, that can clear any corrupted APN (Access Point Name) configurations, remove cached DNS entries created from VPN usage, reset routing tables to default carrier settings, and eliminate network configuration conflicts that VPN usage had created.

Even though Fongo worked with the VPN active, VPNs can simultaneously create background configuration conflicts that can persist after VPNs are disabled.

iPhones can cache DNS responses from the VPN’s DNS servers, which may conflict with direct cellular DNS queries when the VPN was off. During a VPN session every DNS—whether it comes from Safari, an app, or the operating system itself—passes through the VPN tunnel, is answered by the VPN-designated resolver, and is then stored in that cache. When the tunnel is dropped, iOS does not instantly purge those answers; it simply keeps them until they expire. If the VPN’s resolver returned addresses that differ from the public internet, the cache can temporarily conflict with the cellular network’s DNS.

Also, VPN software can modify system routing tables to redirect traffic through VPN tunnels. These modifications can leave residual entries that interfere with normal cellular connectivity.

and go into Fongo to enable Alternate DNS Resolver which made it work again

Fongo’s Alternate DNS Resolver indiciates a DNS‐resolution, rather than specific port blocking.

Anyway, I’m glad Fongo Mobile is working for you at the moment.

FWIW, I keep both Alternate DNS Resolver and Alternate Fongo Connection enabled in Fongo Mobile for LAN networks, and those two settings also work for me while on cellular data.

I’m going to mark this thread as “Resolved” for now, since your troubleshooting steps indicate that Fongo Mobile is working as intended.

[Itzmeeee]

I still need to test it in Vancouver, but so far so good. Thanks for the detailed explanation which makes sense. I'm not sure if it's related, but I also removed an esim spot as well on my phone. I had a travel esim installed for a trip to Thailand. It was already deactivated. After deleting it, there was no resolution so I followed the steps mentioned previously which worked.

[Liptonbrisk]

I still need to test it in Vancouver, but so far so good. Thanks for the detailed explanation which makes sense. I'm not sure if it's related, but I also removed an esim spot as well on my phone. I had a travel esim installed for a trip to Thailand. It was already deactivated. After deleting it, there was no resolution so I followed the steps mentioned previously which worked.

Well, hopefully you've discovered the steps you need to keep Fongo Mobile working on your iPhone should you encounter this problem again. Thanks for posting them.

[Itzmeeee]

Tested it in Vancouver as well, and all appears to be working fine with Fongo. It does sound like what you described about the DNS cache messing things up. Thanks again!

Hopefully if someone else runs into this same issue, these steps may help. PS: on the phone in Vancouver, it was not necessary to delete any unused esims to get it to work.

[Liptonbrisk]

I’m glad the service is still working for you. Thank you for updating, and have a great weekend!