Connection issue with ESP32 SoftAP with Android 10 devices - why?

[ringmybell]

I have setup an ESP32 to act as a softAP serving up a webpage to connected clients. I am using websockets and ESPAsync libraries. Works great...... most of the time.

When connecting newer Android Phones the Wifi connects to the ESP32, then drops off within a second, reconnects, then drops off in a second, reconnects.... and so on. My older Android phones connect no problem as do my windows laptops.

Works
Samsung Galaxy J5 Prime, Android 6.0.1
Sony Xperia Z1 Compact D5503, Android 5.1.1
Toshiba Laptop, running windows 10
Dell G3 Laptop, , running windows 10

Does not work
Motorola Moto G8 XT2045-6, Android version 10
Xiaomi 9T pro M1903F11G, Android 10

So seems to be an issue with Android 10, the Arduino code seems to work fine. Does anyone else have this issue, any ideas on why this happening?

Happens if I upload sketch through Arduino and PlatformIO, using latest ESP32 from Github and latest libraries..

framework-arduinoespressif32 3.10004.201016 (1.0.4)
ArduinoJson 6.16.1
AsyncTCP 1.1.1
ESP Async WebServer 1.2.3
WebSockets 2.3.1

[Bmooij]

In later Android versions you should bind your app to the WiFi connection.

Because later Android versions detect that the ESP32 SoftAP doesn't provide access to the internet, it routes the requests over the cellular connection

[Bmooij]

By disabling the cellular data on your Android 10 phone and connect it to the WiFi access point of the ESP32, it should work fine.

Or if you have access to the app call: bindProcessToNetwork

[ringmybell]

Thankyou for your reply, much appreciated.

Good link, interesting information I did not know about previously. But I am not using any custom apps in my process, and I am not sure which app I would need to modify on the phone, assuming you can modify the source code?

I am trying to get the softAP to act as server and pass webpage over websocket to client when url in webpage is entered. But I can not even get to this point as the wifi drops out. Sorry if I have misunderstood what you have said.

Since this post I learnt about Android debug tool and Verbose Wifi. This shows the access point has been labelled NETWORK_SELECTION_PERMANENTLY_DISABLED. I have searched google but can not find out how I can override this.

As you note it seems to be because the softAP has no internet connection and it is trying to move back to a mobile connection. However, I have the same phones connected to an internet router, I have pulled the WAN ethernet cable (removed internet connection) but do not get the same response from the phone, so maybe the problem is on the ESP32 side.

I have tried all of the following, nothing works. On mobile phone side.....

Disconnecting Mobile 4G
Disconnecting Bluetooth
Turning on flight mode
Every combination of the above
Restarting Wifi
Revert to factory default for Wifi settings
Revert to factory setting for Apps
Downloaded latest Android 10 updates
Used device MAC instead of randomised MAC

On ESP32 side.....

Removed password from softAP

Seems this might be an issue with Websockets or ESP32 wifi libary? Does it need to issue some command to the connected device?

Thanks

[Bmooij]

Can you try to compile your code with the CORE_DEBUG_LEVEL to ARDUHAL_LOG_LEVEL_VERBOSE?
Maybe the Serial output of the ESP32 can provide some information.

[ringmybell]

I think I did the verbose log correct

When using Android 10.....
22:13:06.747 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 16 - AP_STADISCONNECTED
22:13:06.908 -> dhcps: send_offer>>udp_sendto result 0
22:13:06.948 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 18 - AP_PROBEREQRECVED
22:13:09.687 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 17 - AP_STAIPASSIGNED
22:13:11.128 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 16 - AP_STADISCONNECTED
22:13:11.327 -> dhcps: send_offer>>udp_sendto result 0
22:13:11.368 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 18 - AP_PROBEREQRECVED
222:13:19.767 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 17 - AP_STAIPASSIGNED
and then wifi drops off

When I use another Android phone
22:10:49.348 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 16 - AP_STADISCONNECTED
22:10:49.548 -> [D][WiFiGeneric.cpp:337] _eventCallback(): Event: 18 - AP_PROBEREQRECVED
22:10:51.668 -> [1] Connection from 192.168.1.186
and stays connected

[ringmybell]

Is anyone from espressif going to help trouble shoot this? Are they active on this forum?

The softAP does not seem to work with Android 10 devices which are now prevalent in the market, the same Android 10 devices can connect to a Raspberry Pi access point, or a WiFi router with the Modem pulled out, they dont exhibit the same behavior, so it does look like there is something not exactly right with the Arduino code with the more modern Android devices.

[atanisoft]

It works fine on my Android 10 phone when using the SoftAP.

Most likely it is due to the Android system seeking the internet and not finding the dns entries required. Since you haven't included any code we can't really help you solve your code issue.

[Bmooij]

Which ESP32 are you using? And which pins are you using on the ESP32?

[ringmybell]

Are you tweaking some kind of developer setting on the Android 10 phone? Or is just connects straight up?

Even the most basic type of sketch wont work for me, for example this will not work https://shawnhymel.com/1882/how-to-create-a-web-server-with-websockets-using-an-esp32-in-arduino/

I am using ESP32 Pico Kit https://www.digikey.com/en/products/detail/espressif-systems/ESP32-PICO-KIT/9381703

I have tried two different ESP32 pico, same result.

As noted, earlier Android phones and windows laptops are okay. I have just retried the two Android 10 phones I have an neither work on the ESP32 softAP. The exact same phones WILL connect to a Raspberry Pi acting as a softAP or router AP without ethernet connections.

This is my platformIO INO file

[env:pico32]
platform = espressif32
board = pico32
framework = arduino
monitor_speed=9600
lib_deps = 
    ArduinoJson                       
    AsyncTCP                            
    ESP Async WebServer                 
    WebSockets      

[Bmooij]

Can you try a very simple example?

[env:pico32]
platform = espressif32
board = pico32
framework = arduino
monitor_speed=9600

#include <WiFi.h>

void setup() {
  Serial.begin(9600);
  
  WiFi.softAP("ESP32", "123456789");
  Serial.println();
  Serial.println("AP running");
  Serial.print("My IP address: ");
  Serial.println(WiFi.softAPIP());
}

void loop() {}

[ringmybell]

That works.

The same phone connects and stays connected, it does not keep dropping of and trying to reconnect.

[ringmybell]

Okay, I dont understand......

If I change the ssid to anything other than "ESP32" with using a password I am getting the same drop out behavior. In the WiFi debug on my mobile ti says "Check password and try again" Huh? For example I just change ESP32 to ESP33...

#include <Arduino.h>
#include <WiFi.h>

void setup() {
  Serial.begin(9600);
  WiFi.softAP("ESP33", "123456789");

  Serial.println();
  Serial.println("AP running");
  Serial.print("My IP address: ");
  Serial.println(WiFi.softAPIP());
}

void loop() {}

However, the code works if I remove the password as follows.....

#include <Arduino.h>
#include <WiFi.h>

void setup() {
  Serial.begin(9600);
  WiFi.softAP("ESP33");

  Serial.println();
  Serial.println("AP running");
  Serial.print("My IP address: ");
  Serial.println(WiFi.softAPIP());
}

void loop() {}

That seems like very odd behavior ????

[ringmybell]

Anyone have any idea on what is going on?

[ringmybell]

Do any of the developers from espressif look at this forum? As you can see above there is some strange issue happening with the ESP32 Arduino code.

The Android 10 phone works fine with Raspberry Pi acting as a softAP without internet connection, as does connecting to a wireless router with internet disconnected. So I dont think the issue is necessarily with the mobile phone and maybe an issue working with the new Android phones.

[lbernstone]

Have you tested with the development version 1.0.5?