Add code before the closing body tag

Hello,

I’m having a little difficulty in getting a chat bot to operate on my site. The chat bot is from Tidio.

I have been asked to place the supplied code just before the closing </body> tag.

I found an old support reply on placing code dating back to 2014, for adding the following code to Functions.php file:

function add_my_custom_script(){
?>
<script>
PASTE YOUR CODE HERE 
</script>
<?php
}
add_action('wp_footer', 'add_my_custom_script');

But for some reason it is not showing up for me or registering within the Tidio dashboard that I have it installed.

Any assistance is appreciated.

Cheers
John