Debugging POST request ESP8266 PHP

I used Postman to debug my PHP POST API, and it works (ignoring the json versos non-json input).

<?php
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");
//
// include database and object files
require_once '../config/database.php';
require_once '../objects/resdatalog.php';

// instantiate database and resdatalog object
$database = new Database();
$db = $database->getConnection();

// initialize object
$rdl = new Resdatalog($db);

$rdl->Location = $_GET['Location'];
$rdl->Temperature = $_GET['Temperature'];
$rdl->Humidity = $_GET['Humidity'];
$rdl->Pressure = $_GET['Pressure'];
$rdl->RecDate = $_GET['RecDate'];
$rdl->AmbientTemp = $_GET['AmbientTemp'];
$rdl->AmbientHum = $_GET['AmbientHum'];
$rdl->AmbientPressure = $_GET['AmbientPressure'];

$ret=$rdl->insert();

?>

But, the client needs to be an ESP8266 module monitoring the environmentals in various locations. I have been trying to make that work, but debugging has just baffled me. No matter what I display on the client side, it looks OK. But it seems never to actually get to the web page. I put code in the web page to "echo" confirmations, but nothing shows up in the client. What is the best way to debug this setup:

/*
BME280 I2C Test.ino

This code shows how to record data from the BME280 environmental sensor
using I2C interface. This file is an example file, part of the Arduino
BME280 library.

GNU General Public License

Written: Dec 30 2015.
Last Updated: Oct 07 2017.

Connecting the BME280 Sensor:
Sensor              ->  Board
-----------------------------
Vin (Voltage In)    ->  3.3V
Gnd (Ground)        ->  Gnd
SDA (Serial Data)   ->  A4 on Uno/Pro-Mini, 20 on Mega2560/Due, 2 Leonardo/Pro-Micro
SCK (Serial Clock)  ->  A5 on Uno/Pro-Mini, 21 on Mega2560/Due, 3 Leonardo/Pro-Micro

 */

#include <BME280I2C.h>
#include <Wire.h>
#include <ESP8266WiFi.h>
#include <Arduino.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClient.h>
#include <ArduinoJson.h>
#include <ezTime.h>

// ESP8266WiFiMulti WiFiMulti;

#define SERIAL_BAUD 115200

BME280I2C bme;    // Default : forced mode, standby time = 1000 ms
                  // Oversampling = pressure ×1, temperature ×1, humidity ×1, filter off,

Timezone Charlotte;   

String Location;
String Temperature;
String Humidity;
String Pressure;
String RecDate;
String AmbientTemp="0";
String AmbientHum="0";
String AmbientPressure="0";      

const char* ssid     = "mySSID";         // The SSID (name) of the Wi-Fi network you want to connect to
const char* password = "mySSIDPW";     // The password of the Wi-Fi network
//////////////////////////////////////////////////////////////////
void setup()
{
  //set up the serial output
  Serial.begin(SERIAL_BAUD);

  for (uint8_t t = 4; t > 0; t--) {
    Serial.printf("[SETUP] WAIT %d...\n", t);
    Serial.flush();
    delay(1000);
  }


  WiFi.begin(ssid, password);             // Connect to the network
  Serial.print("Connecting to ");
  Serial.print(ssid); Serial.println(" ...");

  int i = 0;
  while (WiFi.status() != WL_CONNECTED) { // Wait for the Wi-Fi to connect
    delay(1000);
    Serial.print(++i); Serial.print(' ');
  }

  Serial.println('\n');
  Serial.println("Connection established!");  
  Serial.print("IP address:\t");
  Serial.println(WiFi.localIP());         // Send the IP address of the ESP8266 to the computer

  waitForSync();


//  Begin the BME setup:

  Wire.begin(4,5);

  while(!bme.begin())
  {
    Serial.println("Could not find BME280 sensor!");
    delay(1000);
  }
  // bme.chipID(); // Deprecated. See chipModel().
  switch(bme.chipModel())
  {
     case BME280::ChipModel_BME280:
       Serial.println("Found BME280 sensor! Success.");
       break;
     case BME280::ChipModel_BMP280:
       Serial.println("Found BMP280 sensor! No Humidity available.");
       break;
     default:
       Serial.println("Found UNKNOWN sensor! Error!");
  }
}

//////////////////////////////////////////////////////////////////
void loop()
{
   printBME280Data(&Serial);
   delay(500);
}

//////////////////////////////////////////////////////////////////
void printBME280Data(Stream* serialclient)
{
   float temp(NAN), hum(NAN), pres(NAN);

   BME280::TempUnit tempUnit(BME280::TempUnit_Fahrenheit);
   BME280::PresUnit presUnit(BME280::PresUnit_inHg);
   bme.read(pres, temp, hum, tempUnit, presUnit);

  Charlotte.setLocation("America/New_York");  
  String localdatetime = Charlotte.dateTime("Y-m-d H:i:s");

   serialclient->print("\tTemp: ");
   serialclient->print(temp);
   serialclient->print("°"+ String(tempUnit == BME280::TempUnit_Celsius ? 'C' :'F'));
   serialclient->print("\t\tHumidity: ");
   serialclient->print(hum);
   serialclient->print("% RH");
   serialclient->print("\t\tPressure: ");
   serialclient->print(pres);
   serialclient->print(" Inches Hg");
   serialclient->println(" Date/Time: "+ localdatetime);
// Now, I'll try to build and post an HTTP command to my cloud API
//
  Location="TiVo Cabinet";
  Temperature=String(temp);
  Humidity=String(hum);
  Pressure=String(pres);
  RecDate=localdatetime;
  AmbientTemp=String(AmbientTemp);
  AmbientHum=String(AmbientHum);
  AmbientPressure=String(AmbientPressure);

    String content = 
  "{\"Location\": \"" + String(Location) + "\"" +
  " , \"Temperature\" : \"" + String(Temperature) + "\"" +
  " , \"Humidity\" : \"" + String(Humidity) + "\"" +
  " , \"Pressure\" : \"" + String(Pressure) + "\"" +
  " , \"RecDate\" : \"" +  String(RecDate) + "\"" +
  " , \"AmbientTemp\" : \"" + String(AmbientTemp) + "\"" +
  " , \"AmbientHum\" : \"" + String(AmbientHum) + "\"" +
  " , \"AmbientPressure\" : \"" + String(AmbientPressure) +  "\"" +
  "}";

  serialclient->println("Content: " + content);


//  Now, we're gonna try to send this line to the server....

  WiFiClient client;
  if (!client.connect("telemetry.shafferassoc.com", 80)) {
    Serial.println("WiFiClient connection failed");
    delay(5000);
  }  else {Serial.println("WiFiClient connection OK");
    }
  client.println("Host: telemetry.shafferassoc.com:80\r\n");
  client.println("POST TelemetryWebSite/API/Resdatalog/Insert.php HTTP/1.1");
  client.println("Accept: */*");
  client.println("Content-Length: " + String(content.length()));
  client.println("Content-Type: application/json");
//  client.println();

  client.println(content);
  Serial.println("Length: " +String(content.length()));
  Serial.println(content);
    Serial.println("receiving from remote server");
  // not testing 'client.connected()' since we do not need to send data here
  while (client.available()) {
    char ch = static_cast<char>(client.read());
    Serial.print(ch);
  }


   delay(5000);
}

Here is a snippet of the Serial output:

11:06:49.892 -> WiFiClient connection OK
11:06:49.892 -> Length: 204
11:06:49.892 -> {"Location": "TiVo Cabinet" , "Temperature" : "73.27" , "Humidity" : "0.00" , "Pressure" : "29.57" , "RecDate" : "2020-04-28 11:06:50" , "AmbientTemp" : "0" , "AmbientHum" : "0" , "AmbientPressure" : "0"}
11:06:49.933 -> receiving from remote server`