Hi.
I already answered your question via email:
”
You don’t need to install any libraries.
The HTTPClient library is the one installed by default that comes with the ESP32 or ESP8266 installation.,
I recommend deleting all the other libraries you’ve installed because they can cause conflict with the original library.
 
Make sure you’re selecting the right board in Tools > Board. Please notice that the code is different for ESP32 and ESP8266.
I also recommend updating your boards’ installation. Go to Tools > Board > Boards Manager, search for ESP32 or ESP8266, and then, update to the newest version.
 
You may also need to follow this trick to fix your installation (even though the problem presented is slightly different): https://randomnerdtutorials.com/solved-arduino-ide-esp32-esp8266-installation/
”
 
Regards,
Sara

Due to a local power-shutdown my email messages arrived later 
 

No worries.
Let me know if you were able to solve your issue.
Regards,
Sara

Hoi Sara,
I followed your advise, deleting the libraries involving httpClients,  without succes.
Though the ESP32 board compiles ok and also my ld-Thinker project but, unfortunately  NOT my nodemcuv1,   which is my most favourite hardware.
Then I looked in the Arduino forum  and came across a  tip to use the basic example
“BasicHttpClient”  and that  did compile.
There are a few differencess  and I got it compiling now changing and adding the lines as follows

//  #include <WiFi.h>    
#include <ESP8266WiFi.h>

//#  include <HTTPClient.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClient.h>
#include <UrlEncode.h>

 
 
AND

void sendMessage(String message){
 
  // Data to send with HTTP POST
  HTTPClient http;
  WiFiClient client;

  String url = “https://api.callmebot.com/whatsapp.php?phone=&#8221; + phoneNumber + “&apikey=” + apiKey + “&text=” + urlEncode(  message);  

  http.begin(client, url);    

It finally compled and works
Thanks
 

I’m sorry, but I don’t understand.
That’s the code that we have for the EPS8266. It uses the ESP8266HTTPClient.h library.
I think you were following the wrong tutorial for the ESP8266.
This is the right tutorial for the ESP8266: https://randomnerdtutorials.com/esp8266-nodemcu-send-messages-whatsapp/
Regards,
Sara

so i invented the wheel again. !!!
So finally it all compiled and flashed.
I added a debug line to display the complete URL line with the following result in the Serial monitor

.......

Connected to WiFi network with IP Address: 192.168.100.63

start

https://api.callmebot.com/whatsapp.php?phone=0031653896647&apikey=4488702&text=Hello%20from%20ESP8266%21

Error sending the message

HTTP response code: 400

When I put this message in the CallmeBot site,  all goes well and the message is received in my Whats App    

so now what…..
 

and yes, i tried the same with the phone number +31653896647 with same result

So sending in in any browser   the message is send fine.

You should use the phone number in international format including the + sign.
In the URL that you posted you don’t have the + sign.
Regards,
Sara

as I did also without different result, no chnge

The 404 code means a bad request.
Please make sure you’re using the right API key for that number and that all the details are correct.
Note that you can only send messages to the number where you requested the API key.
Regards,
Sara
 

When i copy hat cmplete line and paste it in eh location on a webbrowser the message arrives on my whatsapp allright.
Stiil when send by a nodemcu v1 i receive code 400
 

When I try that URL you sent in private I get an error:
APIKey is invalid. Please create a new one or contact support if you lost it.

Make sure you have the latest version of the ESP8266 boards installed.
Go to Tools > Boards > Boards Manager, search for ESP8266 and update to the newest version.
Regards,
Sara

it was aready the newest version but ALAS I uninstalled, restarted the IDE and installed ESP8266 again. compiles goes ok.
But same response

Hi again.
I tested the code again to see if there was something wrong, and it works perfectly fine for me.
So, I’m really not sure why it doesn’t work with your board
Regards,

myomyomy

I changed the secure https to http and, it works.

Probably this is the cause for teh probelem with the firebase project. Totally frustrated I left this project 2 months ago.

Now I have to chase why this did now works on https . I have a server running here which operates on https fine for quite a while

If you want to use HTTPS, check the example here: https://github.com/esp8266/Arduino/blob/master/libraries/ESP8266HTTPClient/examples/BasicHttpsClient/BasicHttpsClient.ino