ESP32 not responding is it the WiFi-router ? or my code?

[StefanL38]

Hi Everybody,

I am using a code that makes use of either these libraries

#include <WiFi.h>
#include <AsyncTCP.h>

#include <ESPAsyncWebServer.h>
#include <ElegantOTA.h> // manual https://randomnerdtutorials.com/esp32-ota-over-the-air-arduino/
#include <ESPDashPro.h>
#include <WebSerialPro.h>

or these libraries

#include <DNSServer.h>
#include <ESPUI.h> // see https://github.com/s00500/ESPUI

#include <WiFi.h>
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>
#include <WebSerial.h>
#include <ElegantOTA.h> // Lu 10.05.2024

in both cases calling the websites created by ESPUI or ESPDash
works always good if the ESP32 is connected to a WiFi-Router AVM FritzBox 4060

but when I connect the ESP32 to an O2 Homebox-router the connection randomly fails with the browser showing an

ERR_CONNECTION_TIMED_OUT - error

What is even more strange an ESP8266 running a similar code works always.
The Ping-time to this ESP8266 is extremely short
mostly in the range of 1 to 5 milliseconds.

The ping-time for the ESP32 is 200 to 500 milliseconds.

Another strange thing is:
even if the ping to the ESP32 does not work exact this ESP32 is able to send UDP-messages to another computer

Huh ??! What is going on here??

So what are your ideas what might cause this behaviour?
And what do you suggest as strategy to narrow down the problem?

Is it the fact that the ESP32 uses unsecured http? (not httpS)?

What would you add to the code to analyse the problem?
enabling most verbose Wifi-debug-output in the ESP32-IDE-options?

always checking

WiFi.status() ?

This O2-Homebox-WiFi-Router has not much to do
waiting for incoming VoIP-calls, a rather old Mini-PC connected with a Cat6-cable
one ESP8266
one ESP32
one ESP32-S3 connected over WiFi

[wildbill]

Good luck; I've found on technical forums that as a frequent poster helping others, you are likely to strike out with your own questions. This because you've probably done all the obvious steps and also, the number of folks who have any chance of assisting, is almost certainly a tiny fraction of the frequent responders.

What I usually start with for network trouble though is Wireshark. Difficult to interpret and there's usually a lot of data to go through, looking for relevant information.