ThingSpeak

here is my code, i want to recive an email notification when my "alerta" field increase.

   % Read the soil moisture channel data from the past two weeks.
  % Send an email and tell the user to add water if the value
  % is in the lowest 10 %.
  % Store the channel ID for the moisture sensor channel.
  channelID = 1425554;
  % Provide the ThingSpeak alerts API key.  All alerts API keys start with TAK.
  alertApiKey = 'TXXXXXXXXXXXX';
  % Set the address for the HTTTP call
  alertUrl="https://api.thingspeak.com/alerts/send";
  % webwrite uses weboptions to add required headers.  Alerts needs a ThingSpeak-Alerts-API-Key header.
  options = weboptions("HeaderFields", ["ThingSpeak-Alerts-API-Key", alertApiKey]);
  % Set the email subject.
  alertSubject = sprintf("Alertas");
  % Read the recent data.
  Alerta = thingSpeakRead(channelID,'NumDays',30,'Fields',8);
      % Get the most recent point in the array of moisture data.
      lastValue = Alerta(end); 
      % Set the outgoing message
      if (lastValue<=Alerta)
         alertBody='alerta de anomalia de fluxo de agua';    
      end
   % Catch errors so the MATLAB code does not disable a TimeControl if it fails
  try
      webwrite(alertUrl, "body", alertBody , "subject", alertSubject, options);
  catch someException
      fprintf("Failed to send alert: %s\n", someException.message);
  end