Problem writing to channel. HTTP error code 400

Hello, I am new to ThinkSpeak so thought I would try your example code for ESP8266 -- ThinkSpeak Channel. Have spent much time making sure all is installed and seems to compile, load and run on ESP8266 Node MCU. Channel is set up and have ID and Author ID I can see the channel but nothing noted. I am getting the above return on serial monitor. Any help very gratefully recieved, please.

[Christopher Stapels]

Did you mean to post the serial monitor output? Im not seeing it.