Duplicate comment detected; it looks as though you’ve already said that!

That duplicate comment detection is handled by WordPress itself, not by your plugins. I’d suggest giving that a try:
https://stackoverflow.com/a/11595416/1045686

That should help.

Jeremy:

Thank you for your assistance.

I found wp-includes/functions.php file. I copy and pasted the code shown between asterisks (***).

**************************************************
add_filter( ‘wp_die_handler’, ‘my_wp_die_handler_function’, 9 ); //9 means you can unhook the default before it fires

function my_wp_die_handler_function($function) {
return ‘my_skip_dupes_function’; //use our “die” handler instead (where we won’t die)
}

//check to make sure we’re only filtering out die requests for the “Duplicate” error we care about
function my_skip_dupes_function( $message, $title, $args ) {
if (strpos( $message, ‘Duplicate comment detected’ ) === 0 ) { //make sure we only prevent death on the $dupe check
remove_filter( ‘wp_die_handler’, ‘_default_wp_die_handler’ ); //don’t die
}
return; //nothing will happen
}

******************************************************************************

I placed that code at the bottom of the file. Saved. When I attempt to open a browser with the site I receive the following message:

Fatal error: Call to undefined function add_filter() in /hermes/bosnaweb03a/b242/ipg.fredprasuhncom/tech-wise.services/150601NAR/wp-includes/functions.php on line 4849

Should I have placed code some other place in the file?

You’ll want to place that code in a functionality plugin, instead of editing core files:
https://www.ads-software.com/plugins/functionality/

Jeremy:

THANK YOU!

I just learned something new about WordPress. I greatly appreciate your patience and wisdom. The “functionality” plugin works great.

fred