Send serial data to local server
As I mention in my answer about serial communication:


  Before reading, always make sure data is available. For example, this is wrong:

if (Serial.available ())
  {
      char a = Serial.read ();
      char b = Serial.read ();  // may not be available
  }

  
  The Serial.available test only ensures you have one byte available, however the code tries to read two. It may work, if there are two bytes in the buffer, if not you will get -1 returned which will look like 'ÿ' if printed.


In your code:


if(Serial.available() &gt; 0)
    {
    server.send(200,"text/plain","Data");
     for(int n=0; n&lt;64; n++)
     {
       data[n] = (Serial.read());



So you know that one byte is available, but you are reading 64. No, that won't work.