Error: simplexml_load_string(): Entity: line 6: parser error : Opening and ending tag mismatch: hr line 5 and body

Url: http://api.inmotek.net/orma_7eb61e503133f1d5498be656deccd474__group.xml?

<html>
<head><title>502 Bad Gateway</title></head>
<body bgcolor="white">
<center><h1>502 Bad Gateway</h1></center>
<hr><center>nginx/1.14.1</center>
</body>
</html>

Fatal error: Uncaught exception 'ErrorException' with message 'Trying to get property of non-object' in /var/www/vhosts/ormabide.com/httpdocs/index.php:68 Stack trace: #0 /var/www/vhosts/ormabide.com/httpdocs/index.php(68): exception_error_handler(8, 'Trying to get p...', '/var/www/vhosts...', 68, Array) #1 {main} thrown in /var/www/vhosts/ormabide.com/httpdocs/index.php on line 68