I'm using this ESP32AsyncDNSServer library on my ESP32 application. Suddenly (I'm not sure what I did) it does not compile anymore:

.pio/libdeps/Aphrodite/ESPAsyncDNSServer/src/ESPAsyncDNSServer.h:8:10: fatal error: AsyncUDP.h: No such file or directory

Here the related code of the library:

#ifndef Stream_h
#include <Stream.h>
#include <AsyncUDP.h>
#include <ESPAsyncUDP.h>

but of course AsyncUDP.h does exist:


What could prevent the compiler to find it?


1 Answer 1


for whatever reason, adding this to your platformio.ini env section helps:

lib_compat_mode = strict # default is "soft"

I guess the more clean version would be to add this to your lib_deps

lib_deps = 
    ESP32 Async UDP # important! otherwise "AsyncUDP.h" blabla is missing..
    <your libs following>

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