When sending a test email I receive the following error message. I am not exactly sure where to start troubleshooting this error. Any assistance would be greatly appreciated.
Request error not JSON:<!DOCTYPE html>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Nothing found for Wp Admin Admin Ajax Php</title>