I have hit the same problem with a couple of apps on an Android phone. The phone has no issue with Internet access using wi-fi. Web browsing and other apps run ok. However, two apps hit connectivity issues when the phone is on wi-fi. During the moments I am facing the problem, if I turn off wi-fi so that Internet connectivity switches to cellular (4G), the apps breeze through immediately.

It so happens that both apps are finance apps. One is a bank's app and the other is a payment app. Both are not related to telcos, ie they don't use cellular for authentication. They have been working fine on wi-fi all along until recently.

What could possibly explain this behavior?

  • What phone and Android versions? Although I doubt this is an "Android issue", do you have "Private DNS" defined and can you go to those sites and login via your mobile browser (not the same always, but a valid test). The suspect here is DNS actually, as your mobile carrier will likely give you unfiltered/public results, but your WiFi may be acting as it's own DNS server or using a filtering list incorrectly or any host of other things. The fact it works on mobile data and not WiFi definitely implies a WiFi issues.
    – acejavelin
    Apr 27, 2021 at 13:55
  • Put the phone in Airplane mode for one minute. Remove from Airplane mode. Wait one minute. This resets the phone's DNS. Does it work now?
    – John
    Apr 27, 2021 at 13:55
  • Yes, a different DNS server from the telco could explain the phenomenon. However, I have just tested with another phone side-by-side connected to the same AP. Both devices are showing the same DNS server ( in use, but the other phone works fine for the problematic app.
    – Old Geezer
    Apr 27, 2021 at 14:33
  • In your case the best chance to understand what is going wrong would be a network dump from the router while the app is making problems. Without such a network trace understanding what is going on is pretty difficult. I don't know how much you know about networks if creating and understanding a network dump in Wireshark is a realistic approach but as I said this is the best option to understand the problem.
    – Robert
    Apr 28, 2021 at 20:50

1 Answer 1


Check WiFi device if you are the owner. Some adjustable features like QoS, priority or Gaming may affect some Apps.

Then check with the provider behind the wireless service. They might have blocked some ports or IP addresses, intentionally for performance or security reasons.

  • I solved my problem without knowing what the causes of the problem were. In my version of Android, there is an option to configure an app to use cellular data only, even if wi-fi is available. This feature is called Mobile data only apps under Data usage in Connections.
    – Old Geezer
    Apr 28, 2021 at 13:23

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