ESP32 – LoRa Sender and Receiver.
Followed schematic, changed arguement to 915E6 to match LoRa board:

//replace the LoRa.begin(---E-) argument with your location's frequency 
  //433E6 for Asia
  //866E6 for Europe
  //915E6 for North America
  if (!LoRa.begin(915E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }
  Serial.println("LoRa Initializing OK!");

Loaded sketch and rebooted ESP32 board all per instructions. But I get the following output and no idea why. 
ets Jun 8 2016 00:22:57
rst:0x1 (POWERON_RESET),boot:0x1b (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:808
load:0x40078000,len:6084
load:0x40080000,len:6696
entry 0x400802e4
LoRa Sender
Starting LoRa failed!
Checked and double checked connections, checked with different LoRa board, then with different ESP32 board. Always the same results.
The only difference I can see is my LoRa board has the W box ticked and your picture of the board bottom showing the freq. of the board (ESP32 Module 6 Unit 2) doesn’t, though I wouldn’t think that makes a difference.
Any ideas what is going on?