Thanks for the reply. I was thinking the same thing too, but in a different way. I thought about using an ESP.restart() once internet is reconnected. I tried it a couple of hours ago and looks like it worked. Restarting the whole system seemed to have fixed the issue. But still it’s weird that it fails to read from firebase even when internet is connected.

By the way, is there any way I could send an unsigned long data to firebase using Arduino library functions (Like Firebase.setInt()… I couldn’t find one for “long” ) ?

For the first part, glad it worked fine!

For the second part of your new question: I really don’t know enough about Firebase to really comment on that, but a quick Google search turned up this: https://stackoverflow.com/questions/31930406/storing-long-type-in-firebase - it might be of use. Otherwise I would recommend asking a new question on this forum, both so everything stays organized but also to make sure your new question gets the attention it deservers (because this one is already marked as solved, not many people will look at it anymore).

I have the same problem. Also, sometime I’ve got Firebase .getInt() failed when power on. So I use ESP.restart() everytime when an Firebase.failed() 

I don’t know why this happens but this trick works for me

you can use ArduinoJson and embedd the long var inside json object https://arduinojson.org/v5/example/

In my case, fix Firebase.cpp AND fix FirebaseArduino.cpp of firebasearduino libs and worked perfectly

1. Change FirebaseArduino.cpp:

   void FirebaseCall::analyzeError(char* method, int status, const std::string& path_with_auth) {
   if (status != 200) {
   error_ = FirebaseError(status,
   std::string(method) + " " + path_with_auth +
   ": " + http_->errorToString(status));
   }

   }

To:

void FirebaseCall::analyzeError(char* method, int status, const std::string& path_with_auth) {
if (status != 200) {
error_ = FirebaseError(status,
std::string(method) + " " + path_with_auth +
": " + http_->errorToString(status));
}
else {
error_ = FirebaseError();
}
}

2. Change FirebaseArduino.cpp:

   int FirebaseArduino::getInt(const String& path) {
   getRequest(path);
   if (failed()) {
   return 0;
   }
   return FirebaseObject(req_.get()->response().c_str()).getInt();
   }

To:

int FirebaseArduino::getInt(const String& path) {
getRequest(path);
if (failed()) {
return -1;
}
return FirebaseObject(req_.get()->response().c_str()).getInt();
}

You can change all get function to: return -1 for your code

No need to reconnect the device to wifi. Just try to add some value to the firebase before checking the connection. This line will helps you.

void loop()

{

Firebase.setInt(“a”,0);

if(Firebase.failed())

{

…

}