Three Mobile Broadband blocks android apps, APN issues 3internet and three.co.uk

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I have just setup my new Three Mobile Broadband Router, a ZTE 888, provided by Three.

The issue I have is several Android apps fail to launch when my Pixel 6 handset is connected to my wifi. These are the My Cupra, Discord, Nectar and the Three apps, which is ironically your app for managing my account. When the apps are launched, they stick on the splash or launch screen. In the case of discord, it opens, but wont load updated feeds. Sainsburys nectar takes ages to refresh.

When I disconnect from the wifi and the three mobile broadband router, and set my phone to use its own 4G/5G connection, all apps launch correctly and function normally. In fact, if I then switch back to the router wifi and the Three mobile broadband they continue to work until closed. My suspicion is that you may be blocking a site that the apps need to connect to? In essence I would expect that the Mobile internet service is an unrestricted service and that no filtering should be in place? I have even turned off the adult filter and checked that no filtering is enabled on the router, none is.

I installed the Three App on another android handset, and get the same result. When I hotspot my second android handset to my Three mobile (pixel 6 handset) I open the three app and it accepts my number and asks for app permissions Next you click goto account, if I were connected to my Three broadband, i'd just get an spinning orange circle that eventually times out with "oops try again". Connected to my hotspot I get presented the logon screen, and can log in. Once logged in, the app works fine no matter the internet connection used. As soon as its closed, the same issues occur again when launched. This never happened with my previous internet provider, so i'm guessing something is causing this related to my Three Mobile Internet Other than these two apps, my connection is absolutely fine and seems to have no further issues.

Having done some further testing and the issue is the APN. When the router is set to "3internet" I get the issues I explained earlier. However if I set the APN to "three.co.uk", the two apps in question work. The issue for me is that I use port forwarding for a security camera and this only works when the APN is set to 3internet. The question is, why does 3internet cause this issue for the two apps in question? Setting the APN to "three.co.uk" stops DDNS and port forwarding working, I suspect this is related to CGNAT on this APN?

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To add, when using the 3internet APN, most google services on android do not work, Authenticator cannot cloud backup, my google nest mini wont connect. 

Three really need to investigate this, its sloppy.

Oh and i've set my router to IPV4 only as IPV4/IPV6 was using CGNAT

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An update on this as I have used my BT Broadband connection for some more testing. Seems the Google Nest mini ironically started having issues randomly saying "there was a glitch" at the same time I connected it to my three mobile.

The Google authenticator app oddly wont sync on BT Broadband or Three Mobile Broadband, only syncs when I switch to 5G on my Pixel 6 Handset.

Lastly, my Barclays Bank App is very slow using the 3internet APN, but fine with the three.co.uk APN

The other issues remain though too. The work around is when in the house, I switch the router to the Three.co.uk APN and when leaving the house, I switch to the 3internet APN, as this allows DDNS to work and Port Forwarding.

In all cases I have disabled IPv6

The question I have to 3 support is WHY?

Why is there a difference between the APNs and why can I not just get 3internet working so I do not have to swap the APNs around.

Its workable, yet, but a faf to remember to change the setting.

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In an interesting twist, after 3-4 days of issues, late on yesterday, my router connected to a different mobile cell, and pretty much everything started working using the three.co.uk APN. Now, yeah, port forwarding still does not work on that, but what I need to test next is how the 3internet APN is fairing. I'm lothe to drop my connection as its ok though. You cannot choose the cell you connect to.

I can only think that maybe the outage on friday took Three some time to fix. Some of the symptoms are in other posts I made, such as Google Nest not working, and twitter not loading or slowly loading images.

Before folks ask, i've tried numerous router reboots so do not think a simple reboot fixed this. The router was connected when it just started working out of the blue.

At some point this week, when this has settled for a few days, i'll test the 3internet APN. When this was enabled there were issues with several android apps not working as they should, however this may have been tied to a wider issue on the three network. It certainly seemed like a DNS problem, slow DNS often causes issues like this. Each APN has its own DNS servers i'd guess, certainly the route tracing is different.

Unfortunately the ZTE 888 cannot have custom DNS set, so i'll probably invest in a better router at some point, especially as an external antenna would be helpful. Modern double glazing does attenuate the signal somewhat.

I'll keep this feed updated as I hope that this experience is useful for others

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Ok, another update, I've switched back to the 3internet APN and all is good so far, so I do suspect an outage on the network that was affecting some sites. Likely DNS related if some were slow. For instance my Barclays online banking was very slow, but is now fine. My Cupra app now launches ok. Twitter is fine too at loading images.

The only anomaly was discord (Android), it still refused to load images and some channels. So, I decided to log in to discord on my phones web browser, and to my surprise, this got the discord app working.

Very odd, but maybe the routing or DNS is a little different between APNs, hence why Discord was ok on "three.co.uk" 

Fingers crossed this keeps working, if it does, my plan is to get a better router with external antennas, so I can maximise my signal reception!